@ Guest...
We where having issue setting up single sign on (After Proper settings has been done as instructed). Finally the issue was as we where using an internal certificate ie was not trusting the site. So once we add it to intranet site in IE from GP for all users it started working. Now only issue is that if i access the site from a non Domain Device/laptop it will give an extra pop up asking for user name and password before showing login screen.
Hope that Helps.