Only order types with internal number assignment are allowed

What causes this issue?

You have entered an <GL:order_type>order type</> that requires external
<GL:number_assignment>number assignment</>. The system can only work
with internal number assignment in the case of maintenance calls.

System Response

INCLUDE 'KEINE-VERARBEITUNG' OBJECT DOKU ID TX LANGUAGE EN

How to fix this error?

Enter an order type with internal number assignment.

Error message extract from SAP system. Copyright SAP SE.