External procurement not defined for material &

What causes this issue?

External procurement is not defined as the
<GL:procurement_type>procurement type</> for the
<GL:material_master_record>material master record</> you entered.


&WHAT_TO_DO& (system administrator)
Check the <GL:material_type>material type</> in Customizing for
Purchasing. The material type determines whether the material is to be
"made in" (manufactured in-house) or "bought out" (procured externally)
- that is, whether internal or external orders may be issued for the
material.
<DS:SIMG.SIMG_CFMENUOLMSOMS2>Define attributes of material types</>

Error message extract from SAP system. Copyright SAP SE.