Hi Suparna
This is most likely because in the sender interface (for proxy) does not have fault message type configured, or the calling program did not catch the application fault (or both).
Make sure:-
1) Configure fault message for sender and receiver interface, create fault mapping for it, and add fault mapping to OM.
2) Make sure the ABAP code includes a TRY-CATCH block to catch the application fault, example below:-
Regards
Eng Swee

