"Certificate issuer untrusted or unknown" security alert

When signing in to an Adobe, I receive the following alert:

This page requires a secure connection which includes server authentication. The certificate issuer for this site is untrusted or unknown...

I am logged in to my Adobe account but on a work computer so I can not upload docs to my cloud, which I don't want to either. I have tried every change in preferences I can make and it still will not allow me to open a pdf without that alert popping and me dissmissing it three times before it will allow me to do anything with the doc. I have tried installing the certificate which did not help at all, tried answering yes three time and then no three times and it stillo continues to pop up.. This is seriously hindering my work performance but I need to use this application at work. I can not access Adobe Creative Cloud website from work as it is blocked as well.