We have had some network issues that caused exchange to keep asking for credentials when users logged onto Outlook. We cleared up this problem, (had a machine with a bot running on it), but I have one user who connects via Sonicwall Net Extender VPN. Now when he tries to connect he gets the Exchange credentials prompt. Even with the correct login info it will not connect. It worked fine before. Any help on this would be appreciated. He is currently on the road so I cannot physical touch his machine.