Hi,
As long as you have:
server type: radius
auth server: ip address of your radius server
used for: user auth
server port: 1645 or exact port that you have configured for use
server secret: as configured on your radius server
verify: same as above
Another thing you can try is to put in your username on the vpn client without the domain name
whilst you are connecting, click under the monitoring tab to see what error you will get.
But you should be good with the advise as set out above