Problem description
The number of Callback requests on the server side exceeds the upper limit.
Causes
Too many Callback requests were initiated in a short period. The server is still processing the existing queue and cannot accept new Callback requests.
Examples
None.
Solutions
Retry the request after a short wait.
References
For information about the causes and solutions of HTTP status code 203, see Errors returned with HTTP status code 203.
For information about the principles of the upload callback feature and how to use the feature, see Upload callback and Callback.
For information about the common errors that you may encounter when you configure upload callback and the causes of the errors, see Upload callback errors and troubleshooting.
For information about how to obtain signature information from the server in various programming languages based on POST policies, configure upload callback, and then directly upload data to OSS by using form upload, see Overview.
For information about how to set up an OSS-based direct data transfer service for mobile apps and configure upload callback, see Set up upload callbacks for mobile apps.