It was not possible to delete all the marked selection versions

What causes this issue?

At least one of the selection versions you chose could not be deleted
because the accompanying selection variant could not be deleted. This
is due to one of the following:
You have no authorization for deleting the variant
The variant is protectected
The variant is locked at the moment

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?

Delete those selection versions that have not been deleted, one by one
and in sequence. The system will then give you more detailed
information as to why the respective selection variant could not be
deleted.

Error message extract from SAP system. Copyright SAP SE.