You can disable “Restrict each user to a single session” on Windows Server 2008 by using “Remote Desktop Session Host Configuration”. But that tool is not available on Windows Server 2012. So we should disable it from local policy to enable 2 sessions at the same time.

Open run and type “gpedit.msc” for Local Group Policy. Go to:

Simply disable “Remote Desktop Services users to single remote desktop session” option.

After that you will be able to connect your server with 2 different session.