It looks like I'm having some problem with my Webgateway in my pre-deployment environment.
I have MWG 7.2.3 installed in WCCP with transparent authentication and NO SSL scanner so far enabled.
When I open an SSL website (specially a static like McAfee Community) it will timeout the https connection after a while. Usually 3 minutes.
All the WCCP settings are fine so far and everything is working except for this SSL timout issue.
By timeout I mean that the page expired and the browser give me back an Unable to find page.
Can I increase the timeout?
This doesn't really sound like a configurable timeout in MWG. Since I am not familiar with WCCP I am not sure... I would recommend to file an SR with support and provide them with a packet capture that shows the problem. That should help us to understand what happens here and find a solution.
This sounds like an issue with your Authentication TTL being very low (3 minutes) and SSL scanner off.
Check out the auth guide regarding hard and soft timeouts: