VTE 4.4.1 - Issue with Customer Portal

Good Morning,

I've a issue with customer portal. When I try to connect to the URL http://MY_VTE_IP/portal and I insert username and password, VTE doesn't allow me to access to the portal.
The application reply me after some time with this error: "Impossibile connettersi al server. Prego contattare amministratore".
There is a log file where I can check If there are any mistakes?

I've installed VTE on Ubuntu 12.04 LTS edition.

Thank you in advance.

Alessandro