Clients take a long time to log off an OWA session after you publish an OWA server and configure OWA forms-based authentication in ISA Server 2004 -- why?

When the S/MIME control is not installed, the Forms-based Authentication logoff program in ISA 2004 causes 2 unnecessary HTTP POST requests to run, slowing down the user's logoff process. This Microsoft article provides information on how to correct this issue.

For more information refer to https://support.microsoft.com/kb/920139/en-us