Connecting Via VPN

[§andro]

I have a user that can not connect to his exchange account via VPN even
though his VPN connection is up and working fine. Occasionally it will work
but very rarely and not for long.

Other users don't seem to have a problem. Also RPC over HTTP refuses to work
on his system, when it works for others.

Can't work out what is wrong as his system is very straight forward and like
other users.

Any help appreciated.