Today I finally decided to look into an issue that I'd noticed for some time. In Outlook 2007 a manual send/receive (F9) would never complete.
An Exchange task would forever say "Offline address book Connecting to Microsoft Exchange." When I looked at Outlook's Connection Status the last line is "Synchronizing Views." I decided to take a look at the IIS logs and found this:
2008-09-03 21:05:52 10.1.1.3 GET /OAB/3ebf24ed-43dc-4a50-a2a9-cc6ef51ebf84/oab.xml - 80 - 74.73.235.66 Microsoft+BITS/7.0 500 19 64 63
Indeed, browsing to that location returns a 500.19 Internal Server Error in IE. While reviewing the root OAB folder in the file system (C:\Program Files\Microsoft\Exchange Server\ClientAccess\OAB\) I noticed a web.config file. I checked another Exchange 2007 server and noticed that it did not have a web.config file in that location. I moved the web.config to another location and that corrected the issue.
On a side note, this also corrects an issue with RSS feeds not updating automatically.