Re-Process failed XI Messages SMQ1 SMQ2

SMQ1 – qRFC Monitor for the outbound queue. Use this transaction to monitor the status of the LUWs in the outbound queue and restart any hanging queues manually
SMQ2 – qRFC Monitor for the inbound queue. Use this transaction to monitor the status of the LUWs in the outbound queue.

RSQIWKEX job — automatically resets the inbound queues.
RSQOWKEX job — automatically resets the outbound queues.

Use the above with caution and in assistance with someone who knows  exactly what these do or read up before you do so.