Only certain keys can be defined for this object in this system

What causes this issue?

For this object you can only define certain keys in this system. The
ALE model specifies that specific lines of this object are delivered to
this system from another sytem. These lines or keys can therefore only
be maintained in this other system and not in this system.

System Response

Warning

How to fix this error?

Make sure that you do not define any objects with reserved keys. You
can find the reserved keys <DS:REPO.RBDCUS52>here</>.

Error message extract from SAP system. Copyright SAP SE.