VPN Connection 721 Error

[BLOWE]

I have a user that is trying to connect to your vpn.

I currently have several users that have no problems connecting to my VPN. Just this one is having all sorts of issues with the 721 error.

Here is the scoop:
My Network: Windows 2000 Advance Server running ISA 2000 (this is the VPN server) and its linked to our DNS server which is Win2000 and Active Directory).
User has Account with the Dial-In access checked.

He starts the VPN connection, he puts in his username and password, hits connect and it goes thru the dialogs like its connecting. But when it comes to Verifying Username and Password, it just hangs.....and we have double and trippled checked his username and password. Even went as far as creating a whole new account.

Clients machine is WinXP SP2. He has not issues connecting our out FTP server which is behind the same ISA machine.

Troubled....and stumped as to what the check.

Any thoughts?
Thanks
Brian

 

[BLOWE]

1 more thing....
Our inside IP scheme is 192.168.1.x
and the clients inside IP scheme is 192.168.0.x

Subnet masks are different as well....

 

[BLOWE]

Okay. Client did a test from home and was able to connect to our VPN that way.
What does he need to check on his business side?
1. Make sure GRE (Protocol 47) is allowed?
2. What ports should he check (to make sure there not blocked or being forward to somewhere else? 1723, 1701?)?

Thanks.