Emails sent from or to Alibaba Mail may bounce with the "554 reject by content spam" error when the anti-spam system detects spam-like content or sender behavior.
Problem scenarios
1. An email sent from or to an Alibaba Mail account fails, and the bounce notification contains the following message:
554 reject by content spam2. An email sent from a mail client fails with the following error: error message: 554 reject by content spam.
3. When you send an email from Webmail, the following message appears: This email failed to send due to an unknown error.
Cause
The anti-spam system rejects emails when it detects a large volume of identical content from the same sender, or when the sender has a history of sending spam or phishing emails.
Notes
Alibaba Mail does not support sending bulk marketing emails. For more information, see Standards and specifications for marketing emails. Use Alibaba Mail for regular business communications to avoid having your emails rejected.
Solutions
1. If you send promotional content, make sure all recipients have opted in. To prevent service disruptions, reduce the recipient count, send from a single account, and lower both the sending frequency and total volume.
2. If the sender has a history of sending spam or phishing emails, stop this behavior immediately and implement appropriate security measures.