We have just added an SSL and new domain name for our OWA installation. I have been testing with my login for a few days and it works great. We released it to everyone else and I have end users reporting they can not log in.
I remoted to their machine and they correct they are unable to login. I tested me login and it works fine. So I hit the https://serverIP/exchange
and they were able to login without issue. It only seems to keep them from logging in when they are using the https://