Final entry indicator set

What causes this issue?

You have increased the order quantity or the limit of a purchase order
for external services despite the fact that the "delivery completed"
indicator has already been set.
Note: The type of this system message (E, W, I) is customizable.

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

System Response

How to fix this error?

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.