Fatal error: Uncaught Error: Interface "ilBuddySystemRelationStateButtonRenderer" not found in /var/www/html/ilias/components/ILIAS/Contact/BuddySystem/classes/states/renderer/class.ilAbstractBuddySystemRelationStateButtonRenderer.php:21 Stack trace: #0 {main} thrown in /var/www/html/ilias/components/ILIAS/Contact/BuddySystem/classes/states/renderer/class.ilAbstractBuddySystemRelationStateButtonRenderer.php on line 21