Fatal error: Uncaught Error: Class "ilAppointmentBaseFileHandler" not found in /var/www/html/ilias/components/ILIAS/Calendar/classes/FileHandler/class.ilAppointmentBookingPoolFileHandler.php:28 Stack trace: #0 {main} thrown in /var/www/html/ilias/components/ILIAS/Calendar/classes/FileHandler/class.ilAppointmentBookingPoolFileHandler.php on line 28