Why are some users not logged off OWA after clicking the Log Off button?

On a front-end server running Exchange Server 2003 or 2000 users are not logged of correctly due to a permission issue on the Logoff.asp page or the /exchweb/bin is configured for Integrated Windows Authentication instead of Basic. For more details and for the instructions on how to correct these configuration issues, refer to https://support.microsoft.com/?kbid=927907.