Improve error message when LDAP user is outside filter

Zendesk issue: https://gitlab.zendesk.com/agent/tickets/20587

From customer:

At the moment we use ldap integration with our AD environment to authenticate users. Also, a filter with a groups is being used. When people are not part of the group, the error they receive is the following: Error message: Could not authenticate from your Ldapmain because "Undefined method 'uid' for nil:nilclass".

Is there a way to give a more clear error message saying i.e. that the user is not able to logon with an "access denied" message?