The material category &1 of the header material &2 is not allowed

What causes this issue?

You want to create components for the material &V2&. However, the
<DS:GLOS.3526BC12AFAB52B9E10000009B38F974>material category</> &V1& is
not allowed for BOM header materials. BOM header materials can be:
<DS:GLOS.3526BBD7AFAB52B9E10000009B38F974>Structured materials</>
Single materials (to which you can assign an empties BOM)
You define the material category when creating a material master
record, after which the material category may no longer be changed.

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?

Choose another material with a material category that is allowed, or
create a new material master record.

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.