phpCAS: Authentication failed with CAS

I have installed a CAS server with a public domain and it works correctly. I implemented PHPCas in the same server and it works correctly too, and I was able to authenticate me on it.

Now I want to use my other public domain with different services with CAS authentication but, after login in CAS, when I redirect to these services, PHPCas tell me “Authentication failed, you were not authenticated”

I have been searching for a long time and I couldn’t find any solution. What I need is to keep the CAS session between two servers.

The configuration of PHPCas authentication is:

phpCAS::client(CAS_VERSION_2_0,'example.com', 8443,'/cas', TRUE);

The url is this: http://client.com/portal.php?ticket=ST-… so the ticket is granted, why is failiing the authentication?

The procedure is the following one:

include_once("../CAS.php"); 
//initialize phpCAS (CAS Version, CAS Server, Port, Base URI, Should phpCAS start a PHP Session?)
phpCAS::client(CAS_VERSION_2_0,'example.com', 8443,'/cas', TRUE); 
 
//For development. Prints out additional warnings. 
phpCAS::setDebug(); 
phpCAS::setVerbose(true);
 
//no SSL validation for the CAS server 
phpCAS::setNoCasServerValidation(); 
 
//force CAS authentication. 
phpCAS::forceAuthentication();

What can I do? setVerbose only tells me the PHPcas version and what CAS server is used. I don’t have any logfile in /tmp (I don’t know why)

Thanks!