Error in namespace prefixes of function; see long text

What causes this issue?

The function module &V1& and the function group &V2& are not in the
same namespace.

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?

Go back a step and generate the function module again.
When you choose the function module name, make sure that it starts
with the same namespace prefix as the function group.

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.