Outlook Web Access receives a "page not found" error message in two frames of a Web page

When you try to use Microsoft Outlook Web Access (OWA) to connect to a Microsoft Exchange 2000 Server computer, you see two frames in your Web browser window. Both frames may contain an error message that is similar to the following:

This behavior may occur if you try to connect to a front-end Exchange 2000 computer that is behind a reverse proxy server.

This behavior occurs because the front-end Exchange 2000 computer sends the client's GET request by using Exprox.dll to the appropriate back-end Exchange computer. The content of the page is based on the host header that the back-end Exchange computer receives in the GET request, and the page is built by using Davex.dll. To the Web browser, the reverse proxy server appears to be the publishing Web server. Therefore, only one set of authentication headers are sent to authenticate the Web browser to the proxy server and to the publishing server. Because the reverse proxy server modifies the host header before it reaches the front-end Exchange 2000 computer, the contents of the OWA page are built incorrectly.

To work around this behavior, you must disable the reverse proxy server and pass the original host header that was typed in the client directly to the front-end Exchange 2000 computer. For more information about how to disable the reverse proxy server, see the documentation that is provided by the vendor of your proxy server.

For additional information about Microsoft Proxy Server 2.0, click the following article number to view the article in the Microsoft Knowledge Base: Microsoft provides third-party contact information to help you find technical support. This contact information may change without notice. Microsoft does not guarantee the accuracy of this third-party contact information. For information about your hardware manufacturer, visit the following Web site: