Hello Vivek,
Service builder would have also generated code for RFC Exception handling to catch exceptions raised when communication fails between your GW and BE for some reasons.
Handling is done for 1. System Failure 2. Communication Failure & 3. Business Failure;
Put a BP in your DPC or DP_EXT class where exception code is written to check what exactly is has caused communication failure.
For your reference : Code would be something like this. Put BP here and check the problem.
*-------------------------------------------------------------
* Map the RFC response to the caller interface - Only mapped attributes
*-------------------------------------------------------------
*-------------------------------------------------------------
* Error and exception handling
*-------------------------------------------------------------
IF lv_subrc <> 0.
* Execute the RFC exception handling process
me->/iwbep/if_sb_dpc_comm_services~rfc_exception_handling(
EXPORTING
iv_subrc = lv_subrc
iv_exp_message_text = lv_exc_msg ).
ENDIF.
Go inside this method and check to get info on what has to be done to resolve issue.
Regards,
Ashwin