SAP Message 5C399 - System error when sending a message (&1, &2)

Diagnosis
To sign, send, or check the signature, messages must be sent to the PI.This caused a technical problem.

System Response
The current process step is terminated. The process changes to an errorstatus.

Procedure
If the problem only exists temporarily (for example, PI was temporarilyunavailable/could not be reached), you can perform the process stepagain at a later point: Manually switch to an appropriate follow-onstatus (for example, "Query Status Again", if the problem occurred whenquerying the notification status) and perform the process again.

Procedure for System Administration
The PI message monitor may contain further details on the cause of theerror. The message was sent on &V1& at &V2& o'clock.
If there is no entry in the message monitor, the problem could be withthe connection of the ERP system to the PI: In view V_T50BK (countrygrouping Switzerland), the RFC destinations are maintained under theconstants 'DEST' and 'DSTXI' and the remote-enabled function modulesthat are used for the ERP system connection to the PI are maintainedunder the constant 'FNAM*'.