SMS signature FAQ
For questions about creating, modifying, or reviewing an SMS signature, see the following FAQ.
Frequently asked questions
Signature real-name registration
Do I need to re-edit and resubmit my signature after my qualification is approved?
Does a promotional SMS signature need real-name registration filing?
Do I need to modify code or API configuration after changing a signature?
How to handle the "Filed for Verification" or "Available-Abnormal" status?
Can I still use existing signatures after enterprise information or account entity changes?
Why do different carriers have different filing progress and success rates?
How to share a signature across multiple apps or business lines?
Messages containing links, contact information, or IP addresses are blocked
Which Alibaba Cloud account should I use to submit a signature application?
How to handle a mismatch between the signature entity and the app ICP filing entity?
Signature application
Can a complimentary signature be modified after it passes review?
What do I do if a complimentary signature is disabled and unavailable?
How do I handle a complimentary signature that is under review?
Can a complimentary test signature be registered with carriers?
Does a signature filing exception affect carrier channels that have already been filed?
What can I do if a qualification issue prevents me from editing my signature?
Signature use cases
Signature review
Individual users
Letter of authorization
Signature status
Signatures from other accounts
Short Message Service does not support signatures from other accounts.
Neutral signature
A neutral signature is a signature that does not identify a specific business. Stricter carrier regulations now prohibit neutral signatures. We recommend modifying your neutral signature to include your name or your company's abbreviated name.
For more information, see the SMS signature specifications.
Is a signature that combines numbers and English letters compliant?
Yes. A domestic SMS signature can consist of Chinese characters, English letters, or numbers. A signature that combines numbers and English letters can be submitted for approval. Signatures cannot contain traditional Chinese characters or special characters, including spaces.
For more information about signature rules, see Signature rules.
Sending SMS with a failed signature
If a signature fails the Alibaba Cloud review, you cannot use it to send messages.
Brief buffer period: If a signature fails carrier registration or is subject to carrier compliance governance, it may retain limited sending functionality before the carrier completely shuts down the channel. However, the delivery rate will fluctuate significantly as the carrier enforces these measures.
Risk warning: Relying on this buffer period carries a high risk of service disruption. A large-scale sending failure indicates that the channel has been closed.
Recommended action: When you receive a review failure or compliance governance notice, immediately apply for a new, compliant signature and complete the registration process. Do not wait until the old signature is disabled.
Personal trademarks and SMS signatures
You cannot use a trademark registered to an individual for an SMS signature, nor can you use a letter of authorization to authorize an enterprise to use it.
If you use a trademark as the signature source, the trademark registrant must be an enterprise entity. This entity must also match the qualification entity associated with the signature. Alternatively, you can establish this connection using a third-party qualification and a letter of authorization.
We recommend either transferring the trademark to an enterprise or using the full or abbreviated enterprise name as the signature source.
Convert a test signature to a production signature
You can no longer create new test signatures. To learn about or test Short Message Service, use the Quick Start feature in the Short Message Service console.
To convert an existing test signature to a production signature, use one of the following methods:
Method 1: For an approved test signature, click Modify. Change the signature source to reflect your business, provide a link and description for your use case, and then submit the application.
Method 2: Delete the test signature and then reapply for a signature on the signature management page.
For details, see SMS signature specifications. For the application procedure, see Apply for an SMS signature.
Real-name registration filing
Real-name registration filing means that Alibaba Cloud submits the real-name information for your SMS sub-port number to carriers or providers.
Sender ID
A sender ID is the number displayed on an end user's device when they receive your SMS message.
For example, the number 106XXX110000000XXXX is a complete sender ID, and [Alibaba Cloud] is the SMS signature.
106XXX11 is the base carrier main port number, and 00000000XXXX is the unique extension code that Alibaba Cloud generates based on the signature [Alibaba Cloud].
A sender ID can be bound to only one signature, but a single signature can be associated with multiple sender IDs. To ensure stable SMS delivery, Alibaba Cloud generates multiple extension codes for each active signature and maps them to different base carrier main port numbers. The number of these resources is dynamically adjusted based on carrier policies. Therefore, you must file your real-name registration information with multiple carriers. Alibaba Cloud generates the sender IDs for this filing only after you apply for a signature.
Cause of the PORT_NOT_REGISTERED error
According to the latest requirements from the Ministry of Industry and Information Technology (MIIT) and carriers for SMS content providers (see the product announcement), you must complete the real-name registration process before sending SMS.
If the real-name registration process is incomplete, sending SMS may fail with the error code PORT_NOT_REGISTERED. This error indicates that the required real-name registration has not been completed for your port number.
Check signature filing status
Log in to the Short Message Service console and go to the Signatures page to check the Filing Status column in the signature list. The Filed status indicates that a carrier has approved at least one extension code for the signature. However, filing speeds for extension codes under the same signature can vary because carriers implement their real-name filing systems on different schedules. Additionally, some carriers cannot synchronize filing results with Alibaba Cloud. Before sending messages in bulk, verify delivery by sending a few test messages to different carriers.
Real-name registration for signatures
After your qualification and signature applications are approved, Alibaba Cloud generates a sub-port number and initiates the real-name registration for you. For existing signatures, check if you need to manually trigger the registration.
For detailed steps, see Signature real-name registration.
Real-name filing duration
The carrier real-name filing process typically takes 5 to 7 business days, but can extend to 10 business days for some carriers. Carriers do not guarantee these timeframes. To ensure the process is complete before you go live, apply for the required qualifications and signature well in advance and allow sufficient time for testing.
Required materials for filing
Both Alibaba Cloud and you, the sender, provide the materials required for real-name filing.
Provided by Alibaba Cloud: Main carrier port details from its partner carriers or the Alibaba Cloud Short Message Service.
Provided by the sender: This includes your business information, corporate identity information (such as company name and Unified Social Credit Code), sms signature, names of associated apps, websites, or trademarks, message type, an SMS sending authorization letter, and the real-name information of responsible personnel, such as the legal representative and the enterprise SMS administrator.
You only need to prepare materials according to the Qualification Information Instructions and sms signature guidelines, and submit applications for SMS qualifications and an sms signature.
Filing process
After your qualification and signature applications are approved, Alibaba Cloud generates sub-port numbers and completes the real-name filing for you. The filing process is triggered differently for new and existing signatures. The following diagrams illustrate the general filing process.
New signatures
After completing the applications for your qualification and signature, Alibaba Cloud pre-generates potential sub-port numbers and initiates the filing with the carriers.
Existing signatures
After completing or updating your qualification and signature information, navigate to the signature management page in the console and click file now. Alibaba Cloud then generates sub-port numbers based on your SMS sending activity and initiates the filing with the carriers.
Low SMS success rate after qualification approval
After your qualification is approved, an initial filing period with the carriers begins. For about a week, send SMS messages in small, frequent batches using phone numbers from the three major carriers. Monitor the delivery success rate trend on the Business Statistics - Sending Statistics page in the console to see if it improves.
If the qualification for your signature is associated with an Alibaba Cloud account that has only individual real-name verification, you must promptly upgrade to enterprise verification or apply for a "qualification for use by others" to comply with current real-name requirements for SMS. You must also update the qualification associated with the signature.
If you are using a signature with a source of "Testing or learning purposes", "Online trial", "Online store on an e-commerce platform", "Official Account or Mini Program", or "Website with an ICP filing"Note, you should stop using it. Replace it with a new signature that meets the strictest requirements and associate it with the correct qualification. This helps complete the carrier filing and improve your SMS delivery success rate.
Note: These five signature sources have been discontinued and can no longer be used for new signatures.
If your delivery success rate continues to decrease or remains unstable for a week after you start sending SMS messages with an approved qualification, go to the Business Statistics - Sending Records page in the console to view specific failure reasons and suggested actions.
The platform optimizes SMS sending strategies to handle issues during the real-name filing period and automatically submits filings for approved qualifications and for signatures that have active SMS traffic. Retry failed SMS messages in small, frequent batches to increase channel coverage and improve the delivery success rate.
Message failures after signature registration
A successful registration status indicates that at least one sub-port number has been approved by a carrier. However, message delivery may still be inconsistent. This happens because carriers build their real-name registration systems at different paces, causing registration speeds for sub-port numbers under the same signature to vary. Additionally, some carriers cannot sync registration results with Alibaba Cloud, meaning some messages may be delivered successfully while others fail. We recommend that you check your signature for compliance and then send messages in small, frequent batches to test delivery before sending in bulk.
Check signature compliance: Signatures with a source of "Official Account or Mini Program", "E-commerce Store Name", "for testing or learning", "Online Trial", or "Website for which an ICP filing is obtained" do not meet the latest carrier regulations. We recommend that you apply for a new, compliant signature.
If the signature source is "Enterprise or public institution name", the signature must be the full name or a short name of the entity. If you use the full name, it must be an exact match. If you use a short name, it must be a continuous segment of the full name, include the brand name, and uniquely identify the entity. The short name cannot be a neutral term, correspond to multiple entities, skip or reorder words, or omit essential information.
Examples:
Compliant example: Hangzhou Alibaba Cloud Network Technology (a contiguous substring of the full name "Hangzhou Alibaba Cloud Network Technology Co., Ltd.")
Non-compliant examples: Hangli Network (skipped characters); Qishangrui Shenzhen (reordered characters); Hangzhou Ali Net (skipped characters)
If the signature source is "Registered trademark name", the signature must be a trademark that is owned by the enterprise and verifiable on the China Trademark Network website.
Check your Signature Source and Signature Name. We strongly recommend using "Enterprise or public institution name" as the signature source to significantly increase your registration and delivery success rates. The carrier real-name registration process takes an average of 5 to 7 business days. Based on recent data, some carriers may take 7 to 10 business days. However, carriers do not guarantee these timeframes, and the process may take longer. You can verify the delivery success rate of your signature by sending messages in small, frequent batches.
Send messages in small, frequent batches: If your signature is compliant and its source and name meet the requirements for either "Enterprise or public institution name" or "Registered trademark name", we recommend sending messages in small, frequent batches to verify the delivery success rate.
Re-reporting after qualification updates
The six key elements of enterprise information are: the unified social credit code, enterprise name, legal representative's name, legal representative's ID, contact person's name, and contact person's ID.
After your qualification is approved, any change to the six key elements of enterprise information automatically triggers a new report.
If there are no changes to the six key elements of enterprise information, the signature's reporting status will change to "Not Reported". Log in to the console, navigate to the Signature Management page, and manually click Report Now to resubmit the signature to the carriers.
After a qualification change triggers a new report, signature editing is locked: the Edit Signature and Edit Associated Qualification buttons are unavailable until the current report is complete, and you cannot submit another qualification change in the meantime.
While a report is in progress, the signature's reporting status is displayed as "Reporting" or "Reported - Pending Verification".
Reporting progress is tracked independently for each carrier (China Mobile, China Unicom, and China Telecom). If the report fails with one carrier, it does not affect sending through other channels that have already completed reporting.
Why is the signature status pending?
This occurs when your signature or real-name information fails to meet carrier requirements. The carrier might reject the filing without reporting the status change, leaving the status as "Pending" in the Alibaba Cloud console.
If you recently submitted a signature for filing, the carrier review is likely still in progress. This process typically takes 5 to 7 business days but can extend to 7 to 10 business days. These timeframes are not guaranteed, and the actual processing time may be longer.
Verify filing status
Verification method: When the filing status changes to "Pending Verification", send verification code or notification SMS messages in small, frequent batches to mobile numbers from different carriers, such as China Mobile, China Unicom, and China Telecom. The platform determines if the filing is successful based on delivery results.
If you have sent messages, check your delivery records for an error message to see if the failure is related to the real-name registration filing. If so, verify that the correct qualification is linked to the signature and that the signature name meets filing requirements.
If the qualification information is inaccurate or incomplete, go to the Signature Management page and click Change Qualification or Edit Current Qualification. After you submit the changes, the platform automatically re-initiates the filing.
If the signature name does not comply with real-name registration filing requirements, apply for a new, compliant signature and link it to the appropriate qualification.
If both the qualification and signature are compliant, continue to send test messages. The platform continuously monitors delivery performance to determine if the delivery is successful.
Improving filing success rate
To improve your filing success rate, ensure your signature is valid and strongly related to your business. Do not submit a generic signature that is unrelated to your business, such as "Cloud OA," "Employee Service Center," or "Sales Compliance Department." Your signature must be derived from one of the following sources, which are listed in descending order of approval rate:
|
Signature source |
Requirements |
|
Enterprise/Public Institution Name (Highly Recommended) |
Full name: Must exactly match the name on the enterprise qualification certificate. |
|
Registered Trademark (Moderate) |
The trademark must be searchable on the China Trademark Network of the National Intellectual Property Administration, and the trademark owner's name must match the enterprise name. |
|
Launched App (Not Supported) |
Carriers no longer support this source. Click to view policy details. |
Incomplete real-name registration
If you send a signature by using an API or SDK, the error code is:
PORT_NOT_REGISTERED.The console displays this error message:
Signature real-name registration filing issue. As required by carriers, each SMS channel must complete real-name registration filing for the corresponding signature.
Using your phone number for verification
Yes, we recommend using your own phone number for verification. This allows you to:
Check that the SMS message is delivered successfully.
Confirm that the message content displays correctly.
Verify that the signature displays correctly.
Preparations: Prepare at least one phone number for testing. For best results, we recommend using one phone number from each of the three major Chinese carriers: China Mobile, China Unicom, and China Telecom.
Purpose of verification: Sending an SMS message allows the carrier to verify the association between your signature and phone number.
Viewing the results: Within 24 to 48 hours of sending the messages, the system automatically checks the delivery rate and updates the registration status to "registration successful".
Do I need to re-edit and resubmit my signature after my qualification is approved?
No. After your qualification is approved, the system automatically initiates real-name registration filing for your signature with the carriers. You only need to wait for the carrier registration result.
Signature filing is the process in which Alibaba Cloud submits the real-name information for your SMS sub-port number to carriers on your behalf. No manual action is required. On the Signature Management page in the Short Message Service console, you can track the filing progress by using the Signature status and Carrier registration result columns. Signature status can be Unavailable, Available - Normal, or Available - Abnormal.
If your signature review fails (Signature status is Unavailable and the review result is Failed), you must click Edit Signature to edit and resubmit the signature. If your qualification is approved, the signature automatically enters the filing process, and you do not need to edit it again.
Does a promotional SMS signature need real-name registration filing?
Yes. All signature types—including verification code, notification, and promotional messages—must complete qualification filing (real-name information) before they can be used. Starting February 1, 2024, SMS sending may be restricted for signatures whose qualification information has not been updated. Carriers also enforce content controls on SMS: content related to exhibitions, promotions, or marketing may be identified as promotional marketing content and blocked.
Mobile numbers and sending frequency
To test a signature, use mobile numbers from all three major carriers (China Mobile, China Unicom, and China Telecom). Use different mobile numbers whenever possible to avoid triggering frequency control.
The following frequency control limits apply:
Verification message: Sending verification messages with the same signature to the same mobile number is limited to 1 per minute, 5 per hour, and 10 per day.
Notification message: Sending notification messages with the same signature and message template code to the same mobile number is limited to 50 per day.
Do I need to modify code or API configuration after changing a signature?
It depends on the specific operation:
Modifying the signature source or linked qualification in the console: These operations do not change the signature name (SignName remains the same), so no code or API changes are needed.
Creating a new signature or replacing an old one (SignName changes): You must update the SignName parameter in your API calls to the new signature name; otherwise, the API call will fail.
Templates and signatures are independent: Changing a signature does not require modifying SMS templates. The template code and signature name are independent parameters in API requests.
AccessKey does not need to be changed: Changing an SMS signature does not involve account authentication, so you do not need to recreate or modify AccessKey (AK/SK).
How to handle the "Filed for Verification" or "Available-Abnormal" status?
These statuses do not mean the signature is permanently invalid. They are usually caused by incomplete carrier filing or compliance policy adjustments. Try the following:
Continue sending small batches: Send verification codes or notification messages in small batches to mobile numbers across all three carriers (China Mobile, China Unicom, China Telecom) to trigger automatic supplementary filing.
Enable the verification code fallback plan: During the transition period, enable the fallback sending plan for verification code messages to ensure business continuity.
Fix compliance issues first: If the abnormal status is caused by a non-compliant signature source (such as "Launched App"), edit the signature to change the source type or apply for a new signature.
Can I still use existing signatures after enterprise information or account entity changes?
Account real-name verification entity or admin change: This does not affect the normal use of approved SMS signatures or SMS templates. Existing signatures and package benefits remain unaffected.
Enterprise name change: If the signature uses an enterprise abbreviation that no longer uniquely corresponds to the new name, the signature may become invalid. Apply for a new signature matching the new enterprise name.
New signatures require new qualifications: After an enterprise name change, you need to upload new qualification materials when applying for new signatures. If the new business license is not yet available, provide a company name change certificate issued by the relevant administration for industry and commerce as supporting material and upload it in the Additional Materials section on the qualification page.
Trademark signatures can be re-linked: If the signature uses a registered trademark, you can re-link it to a new qualification through "Edit Signature" after the qualification is updated.
How to pause SMS sending or prevent signature freezing?
Pause SMS sending: There is no global switch to pause sending. You can achieve this by:
Freezing the target signature on the Signatures page. The signature becomes unavailable for sending. Click Unfreeze to restore it.
Setting account-level sending limits or stopping API calls on the business side.
Prevent signature freezing: If a signature has not sent any messages for 180 consecutive days, it will be automatically frozen. After receiving the freezing warning notification, send at least one message using the signature within the warning period to avoid freezing.
How to troubleshoot the isv.SMS_SIGNATURE_ILLEGAL error?
Follow these steps to troubleshoot:
Verify the signature exists and belongs to your account: Log in to the SMS console Signatures page and confirm the signature name exists under the current account with an approved status.
Check the SignName parameter: Compare the SignName parameter in your API request character by character against the signature name shown in the console. Watch for extra spaces, full-width characters, or encoding differences.
Confirm the signature is not deleted or frozen: Deleted or frozen signatures cannot be used for sending.
Check for cross-account issues: Ensure the AccessKey used belongs to the same account as the signature. Signatures cannot be called across accounts.
Why do different carriers have different filing progress and success rates?
Progress differences: Each carrier has different filing review speeds. China Telecom and China Unicom are relatively faster, while China Mobile has the strictest review and longest cycle (possibly 7-10 business days or longer). Filing progress may also vary by province.
Success rate fluctuations: If messages fail for one carrier but succeed for others, it usually means unfiled channels are concentrated on that specific carrier or province, not that the signature itself is non-compliant.
Strategy: Increase test sending frequency to the failing carrier's numbers to accelerate supplementary filing. Do not abandon the overall filing process due to a single carrier's failure. For detailed filing status troubleshooting, see Status details and troubleshooting.
Does real-name registration require filing SMS templates?
Real-name registration applies only to SMS signatures. SMS templates do not need separate filing. Templates inherit the filing status from their associated signature. You only need to check the filing status on the Signatures page.
Why can some signatures like "Alibaba Cloud" omit location information while my enterprise signature cannot?
Signatures like "Alibaba Cloud" and "JD.com" use the "registered trademark name" source. When a registered trademark is nationally unique, it can be used as a signature without location information. However, when using "enterprise or public institution name" as the source, you must include location information (province, city, or district) to meet the carrier's uniqueness requirements. If your enterprise does not have a registered trademark, you must apply for a signature that includes location information.
How to share a signature across multiple apps or business lines?
If multiple apps or business lines belong to the same qualified entity, use the "enterprise or public institution name" (full or compliant abbreviation) as a unified signature. Differentiate apps or business lines in the message template content. Using a combination like "Enterprise Name + Product Name" is not supported. After a signature passes review, it can be used on websites, apps, and mini programs without restriction.
Messages containing links, contact information, or IP addresses are blocked
Carriers are highly likely to block messages containing links (including short links), contact information, IP addresses, or other traffic-directing information. This is unrelated to signature compliance—changing the signature will not solve the problem. Avoid including any form of link, contact information, or IP address in the message body. Guide users to find information through official channels. If contact information must be included, the success rate depends on the carrier's dynamic risk control policies.
How long does signature/template review take?
Signature and template reviews are typically completed within 2 hours (Monday to Sunday, 9:00-21:00, excluding public holidays). Applications involving government entities may require telephone verification and take up to 2 business days.
Which Alibaba Cloud account should I use to submit a signature application?
The Authorized Party must be the identity-verified entity of the current Alibaba Cloud account. In a third-party authorization scenario, the third party is the Authorizer, and the current Alibaba Cloud account belongs to the Authorized Party. For example, if Company A is the Authorizer and Company B is the Authorized Party, you must use Company B's Alibaba Cloud account to submit the signature application.
How to handle a mismatch between the signature entity and the app ICP filing entity?
If your signature entity does not match the ICP filing entity of your app, on the Signatures page, add or edit a signature, select "third-party use" for the signature purpose, and select a qualification whose entity matches the ICP filing entity. If no such qualification exists, submit a qualification application on the Qualifications page first. Changing the qualification associated with a signature does not affect your AccessKey.
Partial sending failures
The filing progress for carrier channels can vary by region, which can cause sending failures. Additionally, a low sending volume for a signature can hinder the effectiveness of the filing model, leading to persistent sending failures on certain channels, such as China Unicom in specific provinces.
Automatic re-filing mechanism: The system automatically re-files for channels with incomplete filings based on sending failure records. However, this process requires maintaining a sufficient sending volume.
Recommended actions:
Continuously use the signature to send real business messages, not just test messages, in frequent, small batches across different carriers. This triggers the automatic re-filing mechanism and improves channel coverage.
After the filing stabilizes, API calls typically require no further action. However, we recommend maintaining a minimum sending frequency to ensure channel activity.
While waiting for the filing to complete, we recommend enabling a verification code fallback solution to protect your core business.
Signature failures due to carrier compliance
As carriers continue to tighten their compliance requirements, your messages may fail to send in the following scenarios:
Messages blocked due to an oversimplified abbreviated company name: If your signature is an abbreviated company name that is too simple (e.g., "Qishangrui") to uniquely identify your business, carriers will deem it non-compliant and may block messages or deactivate the signature. To resolve this, replace it with a more descriptive, compliant abbreviation that includes regional or industry attributes (e.g., "Qishangrui Network Technology Shenzhen"). We also recommend enabling a verification code fallback solution to ensure business continuity.
Invalid signatures from a "published app" source: Carriers no longer support "published app" as a valid signature source (e.g., "Baitong Online," "ARCFOX"). Even if such signatures were previously approved, they will now have a significantly lower success rate or fail to send completely due to this compliance change. To resolve this, you must replace them with signatures derived from an "enterprise/organization name" or "registered trademark name" source.
Trademark signature fails uniqueness check: If you apply for a signature using a trademark letter of authorization, the filing may fail if the carrier determines the trademark name is not unique (e.g., if many similar trademarks exist). We recommend using your enterprise/organization name or its abbreviation for the filing. After your qualification passes verification, the system automatically grants you a complimentary signature that matches your enterprise name, with the signature source shown as Enterprise/organization name. You can view this signature on the Signature Management page and select it directly in Mass Messaging > New Messaging Task to send messages.
Blocked for Chinese contact information
Reason for blocking: If the body of an SMS message contains Chinese phrases for contact information (such as "customer service hotline" or "inquiry hotline"), carriers may identify the message as a promotional marketing message and block it. This is especially true for verification codes or notification messages.
Signature vs. content issue: This type of block is related to content compliance, not a signature registration failure. However, if a signature registration issue also exists, the system automatically attempts to re-register the signature based on the failure record.
Recommendation: Change the contact information to a numbers-only format, or avoid displaying it directly in the SMS content.
Misleading error codes for signature filing issues
Explanation: Carriers lack a unified standard for error codes. When a signature filing is incomplete, the carrier gateway may return a variety of misleading error codes, such as 'content keyword interception (REJECTD/GB:0010)', 'signature blacklist (LT:0022)', 'throttling limit exceeded (GB:0002)', 'account exception (GB:0015/UK-0002)', or 'ID:0310'. These errors actually indicate an incomplete signature filing or insufficient channel coverage, rather than issues with your message content or account.
Troubleshooting: If your SMS content is free of lead-generation information (such as links, IP addresses, or contact details) and the signature's status is 'Pending Verification' or 'Filing in Progress', the issue is likely with the signature filing.
Solution: Ignore these misleading error codes. To trigger a supplementary filing, send SMS in small, frequent batches to numbers across the three major carriers. We also recommend enabling a verification code fallback solution to ensure business continuity.
Expediting signature filing
No manual expediting: Carriers independently review SMS signature real-name registrations. Therefore, Alibaba Cloud cannot intervene, escalate, or offer a manual fast-track option, and there is no guaranteed completion time.
Official letters cannot replace carrier filing requirements: Signatures must use the full name or abbreviation of an enterprise or public institution, or a registered trademark name. Government-backed projects must follow the same rule. For example, use a signature such as "Tianjin Binhai New Area Transport Bureau Smart Transportation Platform" instead of a generic name like "Smart City Operation Service" that cannot uniquely identify the enterprise.
The only way to accelerate filing: The only way to accelerate the signature filing is to continuously send real SMS messages in small, frequent batches. The system uses delivery failure records to automatically submit supplementary filings to carriers and dynamically validates channel effectiveness based on the delivery rate.
Interim protection: To ensure business continuity while your signature filing is pending, we recommend enabling the verification code fallback solution. If a message sent with your custom signature fails, the system automatically switches to a universal signature to send the verification code. This solution is a temporary measure and does not replace the filing process itself.
Applying for multiple SMS signatures
An individual user can apply for only one general-purpose signature per calendar day. An enterprise user can apply for an unlimited number of general-purpose signatures. For more information, see the SMS signature specifications.
If your account has multiple approved general-purpose signatures and SMS templates, you can use any signature with any template. Signatures and templates are not linked.
SMS signature submission error
A signature must consist of Chinese characters, English letters, or numbers. It cannot contain symbols (including spaces). For details, see the SMS signature specifications.
Signature format requirements
Yes. For details, see signature specifications.
Duplicate signatures across accounts
Yes, the same sms signature can be used by multiple Alibaba Cloud accounts once it passes review.
Business qualifications for gaming signatures
Yes. To use Alibaba Cloud Short Message Service for any gaming-related services, you must provide business qualifications, such as a business license or an online culture business permit.
Troubleshooting signature content verification
If you provide a login link, provide a test account in the scenario description.
Ensure the link you provided is accessible. If it is inaccessible, fix the issue and resubmit the application.
Alibaba Cloud cannot verify content within an app installation package. Instead, provide a download link to your published app.
Alibaba Cloud cannot verify content on internal testing platforms. You must provide a download link from an app store.
If your link is not relevant to the SMS signature, provide a specific business link related to the template. Alternatively, provide the Scenario Path.
If your link leads to a login page and you cannot provide a test account, you can provide screenshots of the business content instead. Ensure sensitive data is redacted from the screenshots so the review specialist can complete verification.
Qualifications for SMS signatures
Alibaba Cloud requires a qualification for SMS signatures to prevent illegal messaging and meet carrier requirements for real-name verification.
Before applying for a signature, apply for qualification for the signature owner. You can use the signature only after both the qualification and the signature are approved.
Signature scope and authorization letter
Yes, the signature you apply for must fall within the scope defined in your letter of authorization. If there is a mismatch, we recommend either submitting a new, compliant signature for review or updating the signature scope in your letter of authorization and resubmitting it before reapplying.
We recommend including all required signatures when applying for a letter of authorization. Once your qualifications are approved, you can reuse the letter for multiple signature applications. This streamlines the process for you and avoids the need to repeatedly sign and seal new documents.
Single signature for multiple websites
If your multiple websites share the same entity information, apply for a signature that is your full company name or short name. For the signature source, select name of the enterprise or public institution. You can then use the signature to send SMS from all your websites.
Can a complimentary signature be modified after it passes review?
After a complimentary signature passes review, its name cannot be modified. On the Signature Management page of the Short Message Service console, click Edit Signature in the Actions column to modify fields such as the use case description, and then submit the change for review.
Deleting complimentary signatures
Complimentary signatures cannot be deleted, but complimentary templates can.
What do I do if a complimentary signature is disabled and unavailable?
Complimentary signatures (marked with the "Gift" tag) must also complete carrier real-name filing. If a signature's status is Available - Abnormal, click the status to view the exception details, and check the Carrier registration result column. If filing is in progress, wait for the carrier's response. If filing has failed, edit the signature to associate it with a different qualification, and then resubmit the filing. Complimentary signatures cannot be deleted, so you can only restore the signature by resolving the filing issue.
How do I handle a complimentary signature that is under review?
A complimentary signature that is under review requires no special action. On the Signature Management page of the Short Message Service console, its status is displayed as Unavailable, not "Under review". After the review is approved, the status changes to Available. You can still apply for new signatures while the complimentary signature is under review.
Can I apply for multiple signatures under the same account?
You can apply for multiple different signatures under the same account, but you cannot apply for a duplicate signature. When you submit a signature application, the system automatically checks for duplicates. If the signature already exists, the console displays the message "The signature already exists. Do not resubmit." and disables the submit button.
Unsupported signature sources
In compliance with requirements from the Ministry of Industry and Information Technology (MIIT) and carriers to regulate the SMS market and protect user rights, the following signature sources are no longer supported:
Official Account/Mini Program: We recommend using an enterprise or public institution name as the signature source.
E-commerce platform store: We recommend using an enterprise or public institution name as the signature source.
ICP-filed website: We recommend using an enterprise or public institution name as the signature source.
Launched app: This source is no longer supported by carriers. For details, see the announcement: Notice on the Discontinuation of 'Launched App' as a Signature Source for Domestic SMS (April 27, 2026).
Testing or learning: To test or learn how to use the SMS service, use the quick learn and test feature in the SMS service console.
Online trial: For applications in a pre-launch or testing phase, we recommend applying for a signature after they are officially launched.
Impact of deleting a signature
Deleting a signature does not affect approved templates. They can still be used with other signatures.
You cannot delete a signature if a related change request is under review. A signature cannot be recovered once it is deleted.
If you need to send SMS messages after deleting a signature, you must update the SignName parameter in your code with a new signature.
Can deleting a rejected signature resolve sending failures?
Deleting a rejected SMS signature does not resolve sending failures. The SMS signature used when you send an SMS message is the one specified by the SignName parameter in your API call, or the one selected on the New Messaging Task page when you use the batch sending feature (Mass Messaging) in the console. It is not the signature associated with your template. If a message fails to send, check whether the SignName parameter in your code refers to a valid, approved signature name instead of deleting the rejected signature.
Gift tag
The gift tag marks a complimentary signature that the system automatically grants once your qualification review is approved. This signature matches your enterprise name, requires no separate application, and is immediately available for sending SMS and for signature registration.
Can a complimentary test signature be registered with carriers?
The gift tag in the signature list identifies a complimentary test signature. After this signature passes review:
Signature status: Displayed as Available-Normal.
Carrier registration: The system automatically submits the signature for registration with China Mobile, China Unicom, and China Telecom. The registration status is displayed as Pending Verification.
Editing and deletion: Complimentary signatures do not support editing or deletion.
Adding a signature: If you need a different signature, use the Add Signature feature to apply for a new signature that meets the standard requirements.
"Testing or learning" is no longer supported as a signature source. If you only need to test the SMS feature, use the Quick Start feature in the console.
Signature changes and filed channels
No impact on filed channels: Editing signature information, changing the associated qualification, or modifying the signature source (for example, from a trademark to an enterprise or public institution) does not affect sending through filed carrier sub-port channels.
Triggers supplemental filing: These modifications trigger a supplemental filing for the new information or for any uncovered channels. During the filing period, we recommend sending messages in small, frequent batches to maintain channel activity.
Exception: If you delete and then recreate a signature, the system treats it as a new signature. You must file all channels again, as the new signature cannot inherit the previous filing status.
Does a signature filing exception affect carrier channels that have already been filed?
A filing exception affects only the new filing for the carrier where the exception occurred; it does not invalidate channels under this signature that have already been successfully filed with other carriers, and those channels remain available for sending SMS. Actual delivery is subject to the real sending result. Because carriers enforce different filing review policies, some messages may still fail to send even after a channel has been successfully filed.
What can I do if a qualification issue prevents me from editing my signature?
If a signature's status is available - abnormal and carrier registration is in progress, the Edit Signature button is disabled, so you cannot directly change the associated qualification. Do the following instead:
On the Domestic Messages > Qualification Management page, click Add Qualification. Upload your latest business license and enter its actual validity period. Make sure the qualification name does not duplicate an existing one.
After the new qualification is approved, go to the Signature Management page and click Add Signature. In the Associated Qualification Name drop-down list, select the newly added qualification.
After you submit, the system automatically starts carrier registration for the new signature. The review takes 5 to 7 business days and does not affect channels that are already registered and active.
SMS sending failure with identical signature names
Avoid creating signatures with the same content for different purposes. A general-purpose signature can be used to send verification codes, SMS notifications, and promotional SMS. To resolve this, delete the dedicated verification code signature.
Cannot submit SMS signature
Check if the signature is already registered for the verification code use case. If so, change its use case to general-purpose. The general-purpose use case supports verification codes, SMS notifications, and promotional SMS.
How to select an SMS signature when sending a message?
Approved signatures and templates can be freely combined to send SMS messages, provided that the use case of the signature matches the type of the template.
If you call an API to send SMS messages, specify the corresponding SMS signature in the SignName parameter when you call the SendSms operation.
If you use Group Messaging in the SMS service console to send SMS messages, select the corresponding SMS signature on the Add Sending Task page. For more information, see Send Group Messages.
If multiple signatures are in filing progress or have failed filing, use the following strategy to select a signature:
Call the
QuerySignatureListoperation or go to the Signature Management page in the console to check the review status of each signature and identify which signatures have passed review and which have not.Send a small number of test messages with each approved signature, compare the delivery success rates, and prioritize the signature with the highest success rate.
Use the full name of your enterprise or public institution, or a registered trademark name, as the signature name. Avoid overly simplified signature names to improve the filing approval rate. For more information, see SMS signature specifications.
Whitelist effect
Effective time: A whitelist takes effect immediately once a number is added.
Scope: Whitelisted numbers are only exempt from the sending frequency limits for verification codes, notifications, and promotional SMS.
Important prerequisites: A whitelist does not bypass signature review or carrier filing. If an SMS signature has not been approved, is in the Available with exceptions state, or has not completed carrier filing, messages sent with this signature will fail—even if the recipient's number is on the whitelist.
Carrier-specific SMS signatures
No, you cannot currently set different signatures for each carrier. Instead, you must select a single signature to be submitted to all three carriers for registration.
Control of signature names and logos
The mobile phone manufacturer, not Alibaba Cloud Short Message Service, identifies and renders the signature name and logo shown on a recipient's device. To change their appearance, contact the mobile phone manufacturer to adjust the configuration or submit the required information.
Inconsistent business entity during signature review
This error indicates the business entity for your signature is inconsistent with your qualification materials. Check for the following:
Typos or other errors in the signature, such as misspellings, or extra or missing characters.
You submitted the wrong document. For example, you uploaded business license B instead of business license A.
Rejection for lack of relevance or third-party rights
Provide a link to your live service and describe the use case. When uploading supporting documents, include a backend authentication screenshot and explain the signature's relevance.
If the signature is intended for use by a third party or involves third-party rights, you must provide a letter of authorization from the signature owner.
If the signature belongs to government or enterprise entities, provide their landline phone number for callback verification.
If the signature owner cannot provide the required documents, you can provide documents from its parent organization and explain the reason in the console's use case description.
For more information about signature rejections, see Recommendations for handling review failure.
Modifying signatures
You cannot modify the name of any approved signature. You can only modify the use case field for signatures with a use case other than 'General'. A modified signature must be reviewed again before it can be used. To avoid service disruption, we recommend applying for a new signature that meets the signature compliance requirements. Once the new signature is available, you can delete any unused old signatures.
SMS signature rejection for non-compliant letter of authorization
For guidelines on how to complete the letter of authorization, see Letter of Authorization Guidelines.
A letter of authorization may be rejected for several reasons, including a missing signature, an incorrect company seal, a missing date, a short validity period, content modifications, or incorrect authorized or authorizing party information. For more details and troubleshooting suggestions, see Troubleshooting SMS Signature Review Failures.
Financial-related signature review failure
Due to carrier regulations governing financial services, Alibaba Cloud Short Message Service supports compliant signatures only for sending verification codes and notification messages. Promotional messages are not supported. To increase the approval rate, ensure you meet the requirements for financial compliance. For details about signature rejections, see Troubleshoot review failures.
Disabled finance and collection signatures
A disabled signature for legal mediation, collection, or finance services cannot be re-enabled. You also cannot use another signature to continue sending SMS for the same type of service. Non-compliance triggers stricter controls.
SMS signature and template review
Alibaba Cloud typically reviews SMS signatures and SMS templates within 2 hours of submission. Reviews are processed from 9:00 to 21:00, Monday through Sunday, but may be delayed during public holidays.
Applications from government and enterprise clients require verification by a landline phone call and are typically reviewed within 2 business days. If your application is still under review after this period, please verify the landline number you provided.
Signature application for individual users
Applications from individual users for a signature for personal use will fail the real-name registration for signatures. You must either apply for a signature for organizational use or upgrade your Alibaba Cloud account to enterprise certification.
When an individual user applies for a signature for organizational use, the signature must be the name of an enterprise or public institution.
Before you apply for a signature, review the usage notes. For specific instructions, see Apply for an SMS signature.
Resubmitting a rejected SMS signature
An individual verified user can apply for only one general-purpose signature per calendar day. For more information, see usage notes.
If your signature application is rejected, follow these recommendations to apply again:
Update the rejected signature based on the reason for rejection.
Delete the rejected signature and create a new one. For steps, see Apply for an sms signature.
Letter of authorization
If user A applies for a signature on behalf of company B, select for others' use as the signature purpose and upload a letter of authorization from company B, authorizing user A.
Applying for all listed signatures
You can list multiple signature names in a single letter of authorization. However, you only need to apply for the signatures your business requires. We recommend listing all potential signatures in your letter of authorization. You can then reuse the letter for multiple signature applications after the qualification review passes.
Modifying an authorization letter
Once the qualifications are approved, the authorization letter cannot be modified.
Third-party SMS signatures without an official seal
Yes, you can apply for an SMS signature. The owner can sign the letter of authorization by hand. You must also state in the use case description that your sole proprietorship lacks an official seal. For more details, see letter of authorization guidelines.
Business license for third-party signatures
If the rights holder is a sole proprietorship, you can submit its business license. If the sole proprietorship lacks an official seal, the operator can provide a signature or fingerprint instead.
Updating signature authorization or qualification
If your letter of authorization expires, click edit signature in the console, upload a new letter of authorization, and resubmit it for review.
After you recertify or update your qualification, associate the new qualification on the edit signature page.
Modifying the letter of authorization or qualification does not affect sending through registered channels, but the changes take effect only after they are approved.
The contact's mobile number does not need to match the one used for the administrator's real-name verification, but it must be able to receive verification codes.
Review status, signature status, and carrier registration result
Review status: This is the result of the review by the Alibaba Cloud platform. Specialists assess the signature's qualifications, format, source, and related materials. After the signature passes this review, its status changes to Approved.
Carrier registration result: This is the result of the review by the carrier. After platform approval, the signature still requires real-name registration with the carrier before you can send SMS. The platform submits your signature materials to this process.
Signature status: This is a comprehensive status determined by Alibaba Cloud based on the review status, carrier registration result, and SMS sending performance. We recommend you monitor the signature status and ensure it remains Available-Normal to avoid SMS sending failures.
Reasons for the unavailable status
A signature's status is not only set to Unavailable when its signature review is not approved. A signature that has been approved and is in use will also have its status changed to Unavailable if it is suspended or disabled for violating regulatory requirements.
You must follow all compliance guidelines, enhance your business security, and send SMS messages responsibly.
Signature status logic
After a signature is approved, its status changes to available - abnormal if it meets any of the conditions in the following table. Otherwise, the signature status is available - normal.
When the signature status is available - abnormal, carriers block all SMS sent with this signature, including verification codes, notifications, and promotional messages, which causes delivery failures. To resume normal sending, troubleshoot and resolve the issue to restore the signature's status to available - normal.
Primary category | Secondary category | Reason | Actions |
Signature Data Anomaly | Signature Information Anomaly | Signature Source Anomaly | Apply for a new signature that complies with the Signature Real-name Compliance Requirements. |
Signature not associated with a qualification | edit signature: Associate an approved qualification. | ||
Signature name does not match qualification | The current signature name and its corresponding source failed verification. Verify that the signature is correctly associated with the enterprise, then edit signature to correct it. | ||
Carrier signature compliance check failed | The carrier's signature compliance check failed. edit signature to comply with the carrier's Signature Real-name Compliance Requirements. | ||
Anomaly with the signature's associated qualification |
|
| |
Signature Power of Attorney Anomaly | Signature Power of Attorney expired | This can affect the delivery rate. edit signature to update the Power of Attorney information. | |
Other | Signature Data Anomaly | This may affect the delivery rate. edit signature to re-initiate the filing. | |
Signature Filing Anomaly | Abnormal filing status | The signature real-name filing failed. | View the carrier filing result for this signature and consult the Signature Real-name Filing documentation. |
Signature Usage Anomaly | Signature Sending Anomaly | The signature has been filed, but its recent SMS delivery rate is abnormal. Check the sending history to identify the cause of the failures. | This signature is experiencing sending anomalies with specific carriers or template types. Go to sending history to view specific failure reasons and recommendations. |
The signature has not been filed (status is not filed, filing, filing failed, or filing invalid), and the recent SMS delivery rate is abnormal. You must complete the filing. | The carrier filing result is incomplete (status is not filed, filing, filing failed, or filing invalid), which may affect the delivery rate. Check the signature's carrier filing result and resolve any issues. | ||
The signature has not been used to send an SMS in the last 170 days, and its information has not been updated. | This signature has been inactive. The platform will suspend it if it remains inactive for over 180 days, and the carrier filing result will become invalid. If you still need this signature, send an SMS before the suspension to ensure the signature remains active. | ||
The signature has not been used to send an SMS in the last n days, and its information has not been updated. | This signature is inactive. Carriers periodically implement policies to manage inactive port numbers. Sending an SMS with a signature that has been inactive for over 30 days may result in an abnormal delivery rate. Keep the signature active by sending messages regularly. |
Handling in-review change requests for frozen signatures
When a signature is frozen, any associated change requests under review are automatically withdrawn. After the signature is unfrozen, these withdrawn change requests are not automatically reinstated. You must edit the signature content (for example, by modifying the signature text or adding supplementary materials) and resubmit the change request to start a new review process. To avoid rework, verify that the signature content is correct before you unfreeze the signature.
Signature status and filing result changes
A signature's status (such as "Available - Normal", "Available - Abnormal", or "Unavailable") and filing result (such as "Filing Successful" or "Filing Failed") can change in real time due to business requirements, policy adjustments, or review feedback. While an edited signature is pending review after resubmission, the signature can still be used to send messages, and its filed channels remain available.
If a signature is frozen, only its filing result may change in real time due to policy adjustments.
For example, a filing result may be dynamically adjusted to comply with external regulation. Regularly check the signature details in the console for the most up-to-date status.
Automatic re-freezing of inactive signatures
If a customer unfreezes a signature but does not use it to send SMS messages for the next 6 months, the system automatically changes its status back to frozen. This policy prevents signature resources from remaining idle and mitigates compliance risks from long-term inactivity.
Fees for frozen signatures
No new charges: After you freeze an SMS signature, the service blocks all sending requests, including API calls. As a result, you will not incur any new pay-as-you-go charges.
Past charges: You will still be billed for messages sent successfully before you froze the signature.
Unfreezing the signature: Billing resumes as soon as you start sending messages with the unfrozen signature. Note that the system automatically freezes the signature again after 6 months of inactivity.
Verification code failure and signature status
Yes. An abnormal signature status is a common reason for verification code delivery failures. When a signature status is Available - Abnormal, carriers block any verification code messages sent with that signature.
To troubleshoot this issue:
Log on to the Short Message Service console, navigate to the signature management page, and check the signature status column for your signature.
If the signature status is Available - Abnormal, follow the suggestions in What determines the 'Available - Normal' and 'Available - Abnormal' signature statuses? to resolve the issue.
After you resolve the issue, the signature status changes to Available - Normal, allowing you to send verification code messages.
Preventing SMS signature suspension
To prevent an SMS signature from being suspended, send a message using the Mass Messaging feature in the Short Message Service console. The sending attempt itself reactivates the signature, regardless of delivery success.
Procedure:
Log in to the Short Message Service console.
In the left-side navigation pane, choose .
Click New Messaging Task.
From the SMS signature drop-down list, select the signature to reactivate. Then, select a message template, enter a recipient number, and submit the task.
Signature freezing is applied independently to each signature. Only a signature that has not been used to send SMS messages for more than 180 days is frozen. Other signatures under the same account that have recent sending records are not affected. They can still be used for SMS sending, signature filing, and template association.
Using signatures with an unconfirmed status
Filed for verification: This status means the signature has passed the Alibaba Cloud review and is pending carrier verification. You can use the signature in your production environment as long as the actual delivery rate meets your business expectations. You do not need to wait for the status to change to 'filing successful'.
Filing invalid: This status typically occurs if you have not used the signature for over six months or due to carrier compliance measures. Although some channels may temporarily remain available, they are highly unstable and can be fully blocked at any time. To prevent service disruption, immediately re-file the signature or replace it with a compliant one.
Evaluation criteria: Use the actual SMS delivery rate as the primary indicator. The status in the console is for reference only and may lag.
Can I edit a signature that is under review?
No, a signature that is under review cannot be edited directly. The Edit Signature button is disabled for signatures in every status on the Signature Management page. To edit the signature, first go to the Review Change Records tab and click Withdraw to withdraw the review process. Then, click Modify Change Request to edit the signature.
How do I submit additional materials after receiving a carrier real-name verification request?
You can submit the additional materials by performing the following steps:
Log on to the Short Message Service console and go to the Signature Management page to find the signature.
If the signature is under review, go to the Review Change Records tab and click Withdraw to withdraw the review process first.
After the withdrawal, click Modify Change Request on the Review Change Records tab to open the edit form.
In the edit form, use the Additional Materials field to upload a screenshot of the app's ICP filing, and use the Application Description field to provide the app store link for the app (starting with
http://orhttps://).After you finish adding the materials, resubmit the signature for review.
Withdrawing the review does not affect sending through carrier channels that have already been successfully filed. After you resubmit, you must wait for the review to be approved.
About the Launched App signature source
Carriers no longer support Launched App as a signature source. In the signature creation and edit forms, this option is disabled and labeled "No longer supported by carriers."