I was debugging an install of Microsoft Exchange 2003 where the authorization dialog kept popping up. I found a Microsoft KB article titled “Troubleshooting Outlook Web Access logon failures” that recommends “Make sure that the Basic Authentication and Integrated Windows Authentication check boxes are not checked [under Authentication and access control for the Exchweb virtual directory], and then click to select the Enable anonymous access check box if it is not already selected.” (Step 2e).
I found that the exact opposite was true. This worked when I disabled anonymous access and enabled basic/integrated authentication. The machine is also a domain controller, so I suspect that anonymous access wasn’t configured for a valid account. I think I’d prefer to leave it with allowing basic authentication on Exchweb rather than anonymous; they’re already presenting credentials for OWA anyway and it prevents anonymous access to server/Exchweb. Comments anyone?