By default, Windows Server 2012 has one remote desktop session enabled. When another administrator logs into the server, the first admin is logged out. Also, Windows Server does not prompt an additional user that two sessions are already active and ask if you would like to disconnect one. The steps below remedy the issue.
- Log into the server and press Windows key + R then type MMC.exe.
- Click on File > Add/Remove Snap-in > click on Group Policy Object > Add> Finish > OK.
- Double click on Local Computer Policy > double click on Computer Configuration > Administrative Templates > Windows Components > Remote Desktop Services > Remote Desktop Session Host > Connections.
- Limit Number of Connections = 999999.
- Restrict Remote Desktop Services users to a single Remote Desktop Services session = DISABLED.