Role &1 not defined in master record for supplier &2

What causes this issue?

The supplier may only operate as a partner for other suppliers (e.g. as
ordering address or invoicing party), not as the supplier who actually
fulfills the order.

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 this is a warning message, you can ignore it.
If this is an error message add partner role &V1& to the supplier master
record:
<DS:TRAN.MK02>Perform function</>

Error message extract from SAP system. Copyright SAP SE.