Wrong general statistis

Hello all,

My Piwik is installed on a subdomain with SSL certificate from CA and monitored statistic the domain with SSL certificate form another CA.

The problem is that the statistics are very, very low. In every days is only a dozen UU. But in fact, there is a 1K UU according to Google Analytics.

My webpage is placed on the engine Drupal.

I do not know where it can be a problem.