Notification &1 is MEB-controlled: Notification cannot be completed

What causes this issue?

Notification &V1& is controlled by the Maintenance Event Builder (system
status 'MEB-controlled') and the assigned revision &V2& &V3& has the
system status 'Created'.

System Response

The notification cannot be completed.

How to fix this error?

If you want to complete notification &V1&, release revision &V2& &V3&
first.

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.