Cannot use partner type &

What causes this issue?

The partner role types you can use in partner maintenance for the
Vendor Master, Purchasing, and Arrangements areas are limited to 'LI'
(Vendor) and 'PE' (HR Master Record), plus, in Retail Industry systems
only, 'AP' (Contact Person).

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?

Error message extract from SAP system. Copyright SAP SE.