monline

The symptom is that if you start Terminal Services Manager (aka. TSM) and double-click on another server of your domain in the list (to get the list of sessions on that TS server), then that server simply disappears from the server list. A possible reason for this might be a denied registry access!

I found a forum topic where they explain that if you try to access a TS server using TSM, it tries to read some registry keys on the remote server. You'll get a "You could not be authenticated on this server" error message if the "Remote registry" service is not running on the TS server that you try to access, or if you've no access to the registry keys that TSM tries to read.

For me the problem was solved only by starting the "Remote Registry" service (since it was disabled, because I thought it is not needed at all ) on the TS servers. However if you've got permission problems, take a look at the following registry key: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurePipeServers\winreg. This key has two subkeys that each contain a multi-string value with a list of remotely accessible registry pathes on that server. In the referenced forum they said that TSM tries to access the HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion key on the TS servers ... so you can start with that in your debugging.

On the other hand, if you cannot allow remote registry access to your TS servers, then you can still use a number of command-line tools to manage them. Eg. you can send messages to remote users via the msg.exe command.