Just had to fight with a similar problem. Turns out that if the local network on the remote side has the same structure as your local network (both local IP adresses are in 192.168.0.0/24 networks for example) then you can't complete the connection. So I had to set up a redirect for the clients IP. Client enters a madeup IP  address in the RDP client and it redirects him to the remote PC. ... View more