2 of 2 people found this helpful
Possibly you're seeing a difference between sAMAccountName (old style non-domain based usernames) and UPNs (eg email@example.com).
Do you have an example of what the difference between the two styles looks like?
This is managed in the AD snap in under the server manager on a per-user basis.
I forgot to answer this, sorry.
Yes that was it. The administrator said they had replicated the server config, but went with the new style account names. That caused lots of fun for the company concerned