Cost element & has an invalid cost element category

What causes this issue?

You want to include cost element &V1& in a resource master record. The
cost element should not be used, because in interval &V2& to &V3&, or
in a subinterval of this, it is not a primary cost element or a revenue
element.
Resources may only be planned together with primary costs or revenues.

How to fix this error?

Check whether you really want to use cost element &V1&. It could be
that it is not possible to plan later in this case.

Error message extract from SAP system. Copyright SAP SE.