You can reproduce the request in the Test console, then mark the checkbox "Device log" and carefully read the JSON log entries. Usually you will find a message with specific error. It works not in 100% of cases, because sometimes I get Internal Service Error without an explanation.
You can reproduce the request in the Test console, then mark the checkbox "Device log" and carefully read the JSON log entries. Usually you will find a message with specific error. It works not in 100% of cases, because sometimes I get Internal Service Error without an explanation.