Normally, you shouldn't have to worry about issues like this.
When you are presented with a certificate issued by an untrusted root authority, your computer will contact the Windows Update web site to see if Microsoft has added the CA to its list of trusted authorities. 1
See Microsoft KB 2328240: "Event ID 4107 or Event ID 11 is logged in the Application log in Windows and in Windows Server"
Cause - This error occurs because the Microsoft Certificate Trust List Publisher certificate expired. A copy of the CTL with an expired signing certificate exists in the CryptnetUrlCache folder.
There is a "Fix it for me" download available at that page, or directions for manually fixing the problem.
After applying the update, and rebooting, the next time you visit the site, your computer should automatically download the CA certificate. Restarting the browser, and re-visiting the site should be successful.
1 - This was paraphrased from the description found in Group Policy Editor (gpedit.msc): Administrative Templates/System/Internet Communication settings/Turn off Automatic Root Certificates Update