Invalid Content-Type in the POST request to the UserDefinedMessage Resource. Only application/json is supported.
Possible Causes
Value of Content-Type in the POST request to the UserDefinedMessage Resource is not as expected, or there is no Content-Type header in the request.
Possible Solutions
Make sure that Content-Type Header is included in the POST request to the UserDefinedMessage Resource and the value of the Content-Type Header is application/json.