Document is not completely canceled

What causes this issue?

,,Cancelling the account maintenance document can cause errors during
updates.

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

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One possible cause of this message is that the cost center has been
lokced for a purchase order with account assignment.
Check the cost center before the cancellation (transaction KS03, view
'Control').
This message is issued in the lists (also in ALV) as an error message,
despite the IMG settings to "Warning message".

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.