I think you're trying to connect to your office computer from home/somewhere else.
If that's the case, make sure you have done the following :
- Your VPN Session is connected
- Your Office IT Administrator allowed RDC over VPN
- Your Office Computer RDC is enabled
- Your User (local or domain user) having administrative rights or allowed to connect to RDC session
- You got no firewall blocking RDC connection or remote registry
To check if you already connected to your office VPN, launch command prompt and try pinging your office computer name or IP Address. As an example if your office computer name is PC-100 and IP address is 192.168.1.100 then you will issue : ping PC-100 or ping 192.168.1.100. If you got ping reply than you're good to go.
To Enable RDC on your office computer there are 2 ways :
1. On your office computer, right click my computer > properties > Remote > Enable Remote Desktop
2. Via remote registry :
- Start > Run > Regedit > Enter/Return
- On registry editor, go to File > Connect Network Registry > Type in your office computer name > OK
- On your office computer registry, browse to : HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\Terminal Server, find the key "fDenyTSConnections", double click it and change the value to 0
You should disable your windows firewall or 3rd party firewall for easier configuration. You can;however set up exception on your firewall but will need some knowledge to do that.
Hope it helps.