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All RFC messages with errors are saved in queues in transactions SMQ1 and SMQ2 for outbound and inbound messages correspondingly. There, messages with errors can be seen with status text and executed again manually. Also, LUW container can be seen there with all information to be sent.
Messages without errors are not shown in transactions above, but integration can be paused to see correct messages as well.
RFC queue can be paused via transactions SMQS and SMQR for outbound and inbound messages correspondingly. To stop the queue:
Select desired destination.
Press Deregistration and confirm.
Type for your destination will be changed from
U. Recorded (stopped) messages can be executed manually via transactions SMQ1 and SMQ2.
Stopped destination can be started again by performing Registration.