Data Cannot Be Saved

What causes this issue?

The service product is involved in this business case. Data is to be
saved for a simultaneous debit memo request and credit memo request.
The design does not allow this constellation.

System Response

The data is not saved.

How to fix this error?

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

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.