I'm having a strange issue with a customer's Exchange server. It's running Exchange 2003 SP2. The Organization setup is a single backend server with two front-end servers (set up as round robin in DNS for load balancing). Forms-based authentication is set up. There is no ISA server nor is there a proxy server involved. OWA is set up to use SSL (certificate is installed and working).
The problem is a single user (out of 4000 mailboxes) gets prompted over and over for authentication in Outlook Web Access. The first log in lets them into the mailbox (preview pane is turned on). If you switch messages, the login screen appears again. If you enter the credentials, then you can view the preview of that message. If you switch messages, the login screen appears again.
I have verified all permissions on both of the front-end servers both in ESM (virtual HTTP) and in IIS. Everything appears to be configured correctly - like I said before, this is one user out of four thousand that has the problem.
I've checked out all the IIS logs and there doesn't appear to be anything helpful there, but I can post that if someone else wants to look at it.
The problem is not local to a workstation - I've recreated it from mulitple workstations on multiple subnets.
Now here's the weird part - if I enter the web address as https://servername/exchange/username
, I don't have the issue. I have checked both front-end servers using that method and the problem never came up once. But if I switch back to the generic https://webmail.domain.com, then it falls apart again.
I'm sort of at a loss where to look next. I did try removing the round-robining (sending everything to a single server) but it didn't help.