Shibboleth session and variables problems

[Andrea Di Mario]

Hi all, i'm a new Shibboleth user. I configured a Shibboleth SP
without problems and it create sessions with IdP. Now, it don't create
any sessions in transaction.log and i can't take shibboleth variable
from apache variables' $_SERVER. My Shibboleth version is 2.0
Apache redirects me on the right IdP page.
On Idp, they told me that they haven't done any change. I had active
the debugging mode on log and there're not errors.

Could someone tell me some possible solution to that?

Thanks for your time.
Best regards.

-- 
Andrea Di Mario
SPEAKAGE