Fedora 21 pam_sss authentication failure - permission denied

Solution 1:

I found the solution to the problem. By running sssd -i -d 4 and trying to log in on a different console, I saw that START TLS was where the login failed. Apparently Red Hat and Fedora by default use TLS. The server does not have TLS (we don't have enough time right now). To disable TLS edit /etc/sysconfig/authconfig on the client machine and update FORCELEGACY=no to FORCELEGACY=yes.

Credit to http://www.linuxquestions.org/questions/linux-enterprise-47/rhel-6-ldap-now-requires-tls-843917/

(Thank you Andy for trying to help!)