Auth prompts on 2012 Server

We have a central mail security console that our exchange servers connect to.  All but our Windows Server 2012 systems check in fine without any issue, but the WS 2012 boxes prompt up the authentication box when trying to add them to our console.

I have verified that the port 8081 is open from the central console

I have verified that Basic, Digest and Forms authentication is enabled

Is there anything else I can check? Or is there a specific issue with running this on a WS 2012 server?  All other systems have the same setup and work fine.

Thanks.