Automatic assignment when changes are made to plan has been deactivated

What causes this issue?

In Shift Planning, you can request an automatic assignment to suitable
requirements when you enter shift abbreviations.
You have deactivated this function.

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?

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.