Fatal error: Uncaught Error: Class "ILIAS\Setup\Agent\NullAgent" not found in /var/www/html/ilias/components/ILIAS/Exercise/classes/Setup/class.ilExerciseSetupAgent.php:30 Stack trace: #0 {main} thrown in /var/www/html/ilias/components/ILIAS/Exercise/classes/Setup/class.ilExerciseSetupAgent.php on line 30