RemoteApp: Logging in as user x disconnects user y

I'm having a pretty bizarre problem with a Terminal Services server used for RemoteApp. In our network the server works as it should, but at a client's office if two users log in simultaneously, the first one gets disconnected as the other one connects. The users belong to the same group but have individual users. The similar configuration works fine for all other clients.

About the server, it's Windows 2008 SP2, no AD, SSL encrypted connections. Event viewer shows no useful information.

Any hints where to start debugging? Do you need more info about the setup?

EDIT: Ok, so the problem has resurfaced with another pair of clients. Similar setup: two users, one group, more than enough CALs. Could this be a problem in the client side firewall/NAT?

Solution 1:

You might not have enough User/Device CALs to host all of the concurrent connections. Terminal Services by default will allow two connections for administrative purposes. If it's a very small office, this problem may manifest itself sporadically as the users inadvertently play "musical chairs" with the two allotted spots.

To check licensing, go to Start menu -> Administrative Tools -> Terminal Services -> Terminal Services Configuration. In the console tree, click Licensing Diagnosis and it will tell you how many CALs you have available (above the two freebies). In the Licensing section it should indicate how the server is licensed and where the license server is located (in your case it may be localhost).