Hi jhardy93, you should not need to add an exception for google.com. As described in an earlier post, you can start the process of adding an exception to call up a dialog that lets you view the details of the certificate to see whether it appears to be from a legitimate source. If you have any doubts, feel free to post what you find here.

For comparison, on mail.google.com (and accounts.google.com, used for login) I get this certificate hierarchy (image attached):

Builtin Object Token: Versign Class 3 Public Primary Certification Authority > Thawte SGC CA > mail.google.com

Builtin Object Token: Versign Class 3 Public Primary Certification Authority > Thawte SGC CA > accounts.google.com

I know I use a proxy server at work, but I can access gmail on IE on Chrome, but just not on Firefox, that is why I though the issue was with Firrefox. I wanted to use gmail on Firefox. I can access https://www.google.com/ and https://www.google.com/calendar both of which are secure connections. I just tried your links above and I can access mail.google.com without being secure. I like to always use https when it is avialable.

Hi jhardy93, I don't have personal experience using a proxy server. When you are not at work, you might have to manually turn off the proxy (i.e., set to No Proxy) if Firefox isn't detecting the change.

orange Firefox button or classic Tools menu > Options > Advanced > Network > "Settings" button

Does your IT support Firefox? Perhaps they have a specific solution for this issue while using their proxy server.

I have been having the same problem, chased my tail around for ages and then realised that my system clock was out of date because my laptop battery is toast.

I reset my clock to today's date and the certificate errors disappeared.

Check your clock?