I have restarted diserver process but it didn't help.
Error 8753 is generic error for plugin failuare. can you please confirm version? and complete stack-trace of error or logs would be helpful.
Attached are the stack trace from arjavaplugin.log and corresponding API log.
If AR versions is 9.1.2 and prior, make sure you are using Spoon 4.0. For AR version 9.1.3 and later, use Spoon 6.0.