Switching from Safari to Firefox, I wanted to use the same proxy settings. My first try was to use the system's settings, as it gets automatic proxy configuration from the right URL. This worked alright for Safari! On Firefox however, if I'm connected to the VPN I can access all websites in our VPN, but none outside, as I get the SEC_ERROR_UNKNOWN_ISSUER (can't always add an exception) As soon as I exit the VPN, firefox is "unable to find the proxy server". I've tried all other kinds of ways to connect via that proxy - manually connecting, by URL in firefox or by automatically detecting, but nothing solves my problem. The automatic configuration shouldn't be the problem as it works fine for Safari and shouldn't be any different for Firefox. I'd really appreciate any help on the subject.