Just want to share some information which might be useful for some of you.
I was playing with a Terminal Services Server (Windows 2008) in a test environment; in particular I was trying different things with TS Web Access and RemoteApps. I have published MS Outlook as a Remote Application available through the TS Web Access, but every time when I was trying to access MS Outlook from the TS Webb Access page (from Windows XP SP3 client PC) I was getting an error:
Your computer’s settings do not allow connection to this remote computer because it cannot be identified. Either it is running a version of Windows that is either earlier than Windows Vista, or it is not configured to support server authentication.
For assistance, contact your network administrator or the owner of the remote computer.
Having checked all setting I found out that the Security Layer for Server authentication and data encryption was set to RDP Security Layer. I have changed the Security Layer to Negotiate and the problem has disappeared.
So, if you will be getting the same error you can check this setting and change it if necessary.