APO Sales Scheduling Agrmnt.: Releases can only be created/changed in APO

Message type: E = Error

Message class: V4 - Nachrichten Verkauf (Variable Meldungen und EDI-Meldungen)

Message number: 329

Message text: APO Sales Scheduling Agrmnt.: Releases can only be created/changed in APO

What causes this issue?

The sales scheduling agreement item is contained in an active
integration model and is planned within APO management of scheduling
agreement releases for sales scheduling agreements.
For sales scheduling agreements which are planned in APO management of
scheduling agreement releases, scheduling agreement releases can only
be created and processed in the APO System.

System Response

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

How to fix this error?

Maintain the scheduling agreement releases in the APO System or remove
the corresponding sales scheduling agreement items from the active
integration model.