bgRFC destination &1 missing; check Application Operations Guide

What causes this issue?

A required background RFC (bgRFC) destination is missing. This prevents
reliable processing of asynchronous updates between documents.

System Response

The trigger cannot be created as bgRFC trigger but is saved in the
trigger database table to avoid data loss. Use transaction
/SCMTMS/PROC_TRIGGER to process the triggers.

How to fix this error?

Check the maintenance of the bgRFC inbound destination as defined in the
Application Operations Guide for Transportation Management to enable
normal trigger processing.
Use transaction /SCMTMS/PROC_TRIGGER to process the triggers that have
been stored in the trigger database table.

Procedure for System Administrators

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

Error message extract from SAP system. Copyright SAP SE.