I have access to Drupal and CiviCRM admin but for half the DRUPAL pages I get a white page. (apparently CiviCRM works fine). Something is crashing the website and I don't understand what. I still can access to Drupal Logs and they don't show anything special. I have no idea where to start from.
What is unclear is that I have a drupal multisite functioning with sub folders /site1 /site2 and only 2 from 3 don't work anymore. So this issue is really related to some special parameters I can't find.