ISA Proxy 502 Error....

If you try to access a website like http://mail.google.com and you get no issues with accessing the website, but when you try to use the secure version (https://mail.google.com) using SSL you get the error:
Network Access Message: The page cannot be displayed
Technical Information (for Support personnel)

Error Code: 502 Proxy Error. The specified Secure Sockets Layer (SSL) port is not allowed. ISA Server is not configured to allow SSL requests from this port. Most Web browsers use port 443 for SSL requests. (12204)

IP Address: 0.0.0.0

Date: 22/01/2008 13:42:22

Server: proxy.a6n.intra

Source: web_proxy

This means that if you employ a filtering solution then you have not excluded the HTTPS address, this occurs because when web filtering applications block websites they remap the port to a port other than TCP:443 therefore you need to the site (in this case) https://mail.google.com!
NOTE : If you get support for this error message you will be advised to add a tunnel for 443 using IsaTrpe this WILL NOT WORK as ISA is not at faulty it is your web filtering software........
Websense remaps blocked HTTPS addresses to 1739

SurfControl remaps blocked HTTP addresses to 1984