Hi,
I think you should follow below given link first and then start thinking
what steps you have missed in your set up and correct them.
<
https://fedorahosted.org/sssd/wiki/Configuring%20sssd%20to%20authenticate...
<
http://www.chriscowley.me.uk/blog/2013/12/16/integrating-rhel-with-active...
--Regards
Ashishkumar S. Yadav