We are working on migrating from Exchange 2003 to Exchange 2007 and just have a small number of pilot mailboxes moved over. All of the sudden about 3 users out of the 10 or so that would use Outlook Anywhere cannot connect. They all have Outlook 2007, and they just repeatedly get prompted for credentials. I do not know of anything that has changed recently other than some windows updates that might have gotten installed.
My troubleshooting seems to point to this being a problem per computer not per user. Some of the users have Windows XP and some have Vista. All windows vista computers work, and XP is mixed. Some work and some don't. For the computers that do not work it does not seem to matter what user logs in, the problem still happens. On my computer I have no issues. I had a user that is having the issue on their computer log into my computer, which created a brand new profile and everything worked. I went to their computer and did the same thing and I had the problem then. The sure seems to point to it being a per computer problem. People with the problem have tried updating Outlook 2007 to the latest SP, also making sure they are fully up to date from windows update. None of that seems to matter.
All of our external Exchange traffic is coming through the Exchange 2007 SP1 HUB/CAS servers, and I have not heard any complaints from the users getting proxied back to their Exchange 2003 mailboxes, and we have a lot of them using Outlook Anywhere. It seems that the problem is only for people that have mailboxes on Exchange 2007 mailbox server. The prompt from Outlook is coming from the mailbox server, but if they keep entering credentials it sometimes will prompt from an Exchange 2003 mailbox server, probably because they have some shared mailboxes or calendars configured in their outlook profile that reside on an Exchange 2003 server.
I am having a hard time finding a common problem between the people not working. I had 3 people identified with the problem, and this morning one of them seemed to start working without making any changes, but the 2 left are persistent, and it does not seem to matter who logs in to their computer and tries.
I was able to find some failure audits on the CAS server for a person having the issue, saying it was an unknown username or pw, but obviously it is correct because they can come over to another computer and it works just fine for them.
Any help or ideas would be greatly appreciated.