Well, if the smartPad is working then RDP should be fine. The default port for RDP is 3389, however I would be very careful with any network/firewall changes as that might lock out your smartPad.
You could also try to start the robot without the smartPad and see if you can connect then. Or maybe try RDP with another PC and make sure that no antivirus/firewall is blocking RDP on the PC side.
In the meantime, you can also consider using another tool like VNC to get the content of the smartPad.
Best,
Johannes