I'm load balancing SSL frontend to SSL backend Active Directory Federation Servers. When I get to the authentication pop up, I can log in when using IE or Chrome ... but when I try to authenticate via Safari or Firefox, I can't get past the authentication pop up. It just stays on it no matter what I enter. I don't think it's even sending the username/password through because it never comes back and tells me authentication failed after so many attempts. I see no errors in the error logs. Is there some configuration I'm missing that causes issues for Safari or Firefox?