Fatal error: Uncaught Error: Interface "Sabre\CalDAV\ICalendarObjectContainer" not found in /var/www/illumine/vendor/sabre/dav/lib/CalDAV/ICalendar.php:16 Stack trace: #0 {main} thrown in /var/www/illumine/vendor/sabre/dav/lib/CalDAV/ICalendar.php on line 16