It’s a common problem with IE. You access a site and get a certificate error and get the pink address bar when you access the site. The solution is to install the certificate into the “Trusted Root CA” certificate store.
You normally do that by clicking the padlock icon to the right of the address bar then “View Certificates” and then clicking the “Install Certificate” button. Lately, I've come across some instances where the button is missing in action. WTF?
Mr. Google to the rescue and the solution is to right-click the IE icon on the desktop and select “Run as administrator”. (In other words, IE needs to be run as Administrator).
And then there was sweetness and light and verily the button doth appear!