did not find error in message but message is in error

Hi dears,

i got a synchronous message in error.and i checked that in SXMB_MONI.Where its original message is recorded and its response message is in error category of 'Request Message Mapping' .with no error id.

i want to find exact error in its Trace and in error.

can you explain why i am unable to find the exact error ? kindly reply to me.

Thanks and Regards,

Sumit Gupta