Basically I have set up a VPN on our domain. It's functioning perfectly. Clients are able to connect to the VPN and remote to their office computers (PCs). Both Mac and PC users are able to connect just fine.
I have this one Mac user that cannot Remote Desktop to her office computer or any other PC for that matter when connecting through VPN.
The mac was connecting successfully before I changed the IP address of the VPN server. I thought it might be that the DNS cache needs to be flushed so I did that using "sudo killall -HUP mDNSResponder". I haven't tested it since I can't test the VPN from within our network. have to be at home.
Incidentally Remoting to a computer while on the domain works just fine.
All of the settings are correct. I've attached a document that has detailed pictures of all the settings
Mac version 10.7