This may be of help to some people. On my mac i just download the latest 3.4.3 version and opened it from my downloads folder rather than dragging it over into apps. I am able to log into the 3.4.3 version successfully. If I try using the 3.4.2 version that is in my apps folder, I still get the CERT error.
I updated to 3.4.3 on my windows machine, and that seems to have fixed the issue as well.