Partner type & does not exist, display only possible

What causes this issue?

You want to edit a partner profile for the partner type &v1&. However,
this partner type is not available.

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?

If you no longer want to use the partner type &v1&, you must delete its
partner profiles. If partner type &v1& is used, you maintain this using
the transaction <DS:TRAN.WE44>partner types</>. You must then restart
the maintenance of the partner profiles

Error message extract from SAP system. Copyright SAP SE.