I am having a strange problem and I am having trouble figuring it out. We have a Windows 2008 R2 Server that will not accept RDP connections from Vista, Windows 7, Windows 8, or other Server 2008 computers/servers. This server is setup for Terminal Services and also its own licensing server but thats it. It is a virtual server in a domain environment that is all new.
When I adjust the security layer from the default 'Negotiate' to 'RDP Security Layer', I am able to access the server regardless of the OS that I am RDPing in from. Note, that I am able to reach the server regardless of the security layer settings from a Windows XP workstation with the latest RDP client (7.0). When connecting in from a non-Windows XP computer with the default security layer of 'Negotiate', I am prompted for credentials before I even connect into the Terminal Server. Now this is where I am at a loss, when entering ANY domain user credentials that I am sure have access to the Terminal Server the credentials are rejected. If I use a LOCAL user, I am able to access the server. Any thoughts?