I ran into one of these just the other day. The problem is with the Web server that you’re connecting to, not the ISA firewall. However, in order for you to connect to these sites, you’ll need to do a little “breaking” of the ISA firewall (just like how some orthopedists need to break some bones in order to get them to work better).
To fix this 502 Proxy error through the ISA firewall (and the TMB firewall as well), check out:
BUT — you’re not done yet. After installing the hotfix, you need to create a Registry entry. You’ll find that information here:
Thomas W Shinder, M.D., MCSE
Sr. Consultant / Technical Writer
Prowess Consulting www.prowessconsulting.com
PROWESS CONSULTING documentation | integration | virtualization
MVP — Forefront Edge Security (ISA/TMG/IAG)