VPN error 721

Hi,

I recently switched from SDSL to T1 and everything works great except for my VPN server, for some reason the clients can’t access the server anymore. I have changed the IP on all the clients to the new one but I’m getting error 721 when trying to verify the user name and password.

We went from a speedstream DSL router to a cisco 1720 router and we also have a sonicwall for our firewall but all the config. have been the same on the firewall. Could this have to do with the cisco router? Are there any new settings I should know about? Please Help!!!!