Troubleshooting OWA's "Loading" Message

I use Outlook Web Access (OWA) 2003 a lot. When I'm on the road, using OWA is often more convenient than unpacking and deploying my laptop and launching Outlook. I'm not alone: As OWA approaches Outlook's desktop version in functionality, more people are using the Web version as a primary client, particularly in organizations that are using the new functionality in Windows Server 2003, Exchange Server 2003, and Outlook 2003 to consolidate Exchange sites. As a result, I've received an increasing number of questions about OWA, in particular about one common problem: When a user launches OWA, it just sits there displaying the message "Loading...". This problem can happen for one of several reasons, most of which are relatively easy to identify and troubleshoot.

The first possible cause is that WWW Distributed Authoring and Versioning (WebDAV) verbs are being blocked between the browser and the OWA server. You should use Secure Sockets Layer (SSL) to protect your OWA sessions, so this type of blockage usually occurs at a proxy server on the client's network or on the firewall at which the SSL session terminates. The simplest workaround for this problem is to use the Basic OWA client, which you can select via the radio button on the OWA 2003 logon page. You can use OWA segmentation to force the use of the Basic client for all users, although doing so means that users will lose a significant amount of OWA functionality. You could also trying to fix the proxy or firewall so that it doesn't block WebDAV verbs, but that isn't always possible.

Another potential cause of the "Loading" problem is that users haven't specified a language preference for Microsoft Internet Explorer (IE). Without a specified language, OWA can't tell which version of the interface to deliver, and instead of guessing, it just petulantly sits there. To fix this problem, have users specify the language you want them to use.

A couple of other possibilities exist if you're still using the ancient Microsoft Proxy Server 2.0 or if you've hit a particular bug; the Microsoft article "Troubleshooting OWA when the contents frame displays 'Loading'" ( http://support.microsoft.com/?kbid=280823 ) discusses these less-likely problems and how to fix them. In addition, the article provides some extreme actions to take if the more typical solutions don't work. The first of these actions is to reregister the msxml.dll and msxml3.dll processing libraries on the Exchange server--something that wouldn't typically strike me as being particularly useful. The other recommendation is to remove and recreate the Exchange virtual directories--not something to approach lightly.

Of course, because OWA depends on Windows and Microsoft IIS, these troubleshooting tips are just a few of many possible procedures. What's your favorite troubleshooting tip? Let me know and I'll summarize the best ones in a future column.