Questa è semplice 🙂 la metto più che altro come nota mia personale in modo da trovare subito il path della policy da modificare. By default on Windows 2012 the ability to simultaneously connect to the same account on different sessions via RDP remote desktop services is not enabled.
To enable this option you must edit a local policy of the server:
1. launch gpedit.msc
2. Go to: computer configuration -> Administrative Templates -> Windows Components -> Remote Desktop services -> Remote Desktop Session Host -> Connections.
3. Disable the option “Restrict Remote Desktop Services user to a single Remote…”
4. Done this, open a command prompt and launch the command fo the new setting to take effect: gpupdate /force