Error in processing workflow DCN Request

Hi supexperts,

required a help in DCN message Notification.

getting error in SUP like error in processing workflow DCN request, this error is coming while try from Firefox RESTClient. if we try with SUP workspace message delivers successfully without any error.

the same message is not pushed from firefox, Request response status code is 200 ok and the body statusMessage is error in processomg workflow DCN request:null

please help me to resolve the problem.

Thanks,

Boopalan.M