Naming Convention for Functional Location &1 is not correct

What causes this issue?

The naming convention for the functional location is not correct. The
reason for this could be:
You have entered a functional location (to be created) but it does not
correspond to the prefix you have already chosen.
You have entered a functional location that already exists in the
system.

System Response

Creation of this functional location is not possible. Assigning an
existing functional location to the structure is not supported in the
"Load Template" scenario.

How to fix this error?

Enter a functional location that corresponds to the naming convention
(prefix) and that does not exist in the system.

Procedure for System Administrators

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

Error message extract from SAP system. Copyright SAP SE.