The procurement type of the special procurement type is &

What causes this issue?

Only one specific procurement type (external procurement or in-house
production) is allowed for the material in this plant. A different
procurement type is assigned to the special procurement type entered.
This is not allowed.

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?

Please correct your entry.

Error message extract from SAP system. Copyright SAP SE.