No purchase order item

What causes this issue?

An error has occurred during the updating of the "delivery completed"
or final invoice indicator in the purchase order item. The PO item does
not exist.

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?

INCLUDE NA_FEHLER_SYSTVERW LANGUAGE EN

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.