To work around this behavior, use one of the following methods.
Use Secure Sockets Layer (SSL) for OWA
Microsoft recommends that you configure SSL for OWA.
For additional information about how to configure SSL, click the article number below
to view the article in the Microsoft Knowledge Base:
299875 HOW TO: Implement SSL on a Windows 2000 IIS 5.0 Computer
Contact the Firewall Manufacturer
Contact the manufacturer of your firewall to inquire about the availability of a fix for this behavior.
For information about how to contact your firewall manufacturer, click the appropriate article number in the following list to view the article in the Microsoft Knowledge Base:
65416 Hardware and Software Third-Party Vendor Contact List, A-K
60781 Hardware and Software Third-Party Vendor Contact List, L-P
60782 Hardware and Software Third-Party Vendor Contact List, Q-Z
Use an Early Web Browser Version
Use an earlier version of Web browser such as Internet Explorer 3.x, 4.x, or NetScape Navigator 4.x that do not use the WebDAV extensions.