Content ID key is still used. Cannot delete.

What causes this issue?

The selected <DS:DE.J_7LFUELLG>content ID</> is still used in the REA
master data.

System Response

The content ID cannot be deleted.

How to fix this error?

First delete the content ID from the REA master data. To do this, choose
REA Information Systems -> Assignment -> Article to ->
<DS:TRAN.J7LIZAR>Recycling Partner</> or Article to ->
<DS:TRAN.J7LIZAV2>Packaging (Recycling Partner-Dependent)</> or
Packaging to -> <DS:TRAN.J7LIZVR>Recycling Partner</>.
Instead of deleting, you can suppress the use of the content ID by
deactivating it.

Procedure for System Administrators

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.