Search scope is not valid &1

What causes this issue?

The search was executed with a category, connector, template, keyword or
request that is not valid. The cause could be that the related list of
search connectors no longer exists.

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 that the scope with the specified key does still exist.

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.