Business area & not assigned to a controlling area

What causes this issue?

Company code &v1& has not been assigned to a controlling area.
Specifically, it is not assigned to controlling area &V2&.

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?

Check your entries.

Error message extract from SAP system. Copyright SAP SE.