Problem description
The callback request returns an error because the callback server's response body is not valid JSON.
Causes
The response from the callback server is not in the valid JSON format.
Examples
Valid response
HTTP/1.0 200 OK
Server: BaseHTTP/0.3 Python/2.7.6
Date: Mon, 14 Sep 2015 12:37:27 GMT
Content-Type: application/json
Content-Length: 9
{"a":"b"}If the data returned by the server to OSS is not in the valid JSON format, an error is returned.
Solutions
Check the logic of your callback server and verify that the response is valid JSON before deploying.
To test without involving OSS, send a POST request directly to the callback server using code or Postman.
For common callback configuration errors and their causes, see FAQ.
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 callbacks and Callbacks.
For more information about the common errors that you may encounter when you configure upload callbacks and the causes of these errors, see Upload callbacks.
For more information about how to obtain signature information from the server in various programming languages based on POST policies, configure upload callbacks, and then directly upload data to Object Storage Service (OSS) by using forms, see Overview.
For more information about how to set up an OSS-based direct data transfer service for mobile apps and configure upload callbacks, see Set up upload callbacks for mobile apps.