Open the Group Policy MMC (type gpedit.msc in the Run window). Go to Computer Configuration, Administrative Templates, Windows Components, Internet Explorer. There is a setting that says "Make proxy ...
If you go into the Group policy the users are in and re configure their internet connection to "dial up to the internet" when they are on a LAN it will not let them connect to the internet with those ...
Most people using Internet Explorer have encountered a security certificate error such as "There is a problem with this website's security certificate" at some point ...