Object type & not defined as classifiable object

What causes this issue?

Object type &V1& is not defined as classifiable. Before you can
classify an object, you must define the object type concerned (for
example, material, document, task list) as classifiable in Customizing
for <ZH>Classification</>.

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?

For information on how to define object types as classifiable, see the
IMG for <ZH>Classification</>.

Error message extract from SAP system. Copyright SAP SE.