Fatal error: Uncaught Error: Interface "ILIAS\UI\Component\Symbol\Avatar\Avatar" not found in /var/www/html/ilias/components/ILIAS/UI/src/Component/Symbol/Avatar/Letter.php:23 Stack trace: #0 {main} thrown in /var/www/html/ilias/components/ILIAS/UI/src/Component/Symbol/Avatar/Letter.php on line 23