Check the tRFC Status
tRFC calls that transfer IDocs use the function module IDOC_INBOUND_ASYNCHRONOUS on the receiver side.
If an IDoc in the sending SAP system has been passed to tRFC (IDoc status "03"), but has not yet arrived at the receiving system, the tRFC call has not yet been executed.
Activities
To check the status of the tRFC calls, choose 
Tools
IDoc Interface/ALE
Administration
Monitoring
Troubleshooting
RFC Queue (SM58)
and specify any additional selection criteria.
The program RSARFCEX restarts unsuccessful tRFC calls.
Note
You cannot choose the option is being executed
in background processing.
End of the note.