Fatal error: Uncaught Error: Call to undefined function add_filter() in /users/laufgruppe-lvb/www/wordpress/wp-content/plugins/eventon-action-user/includes/admin/class-admin_lang.php:6 Stack trace: #0 /users/laufgruppe-lvb/www/wordpress/wp-content/plugins/eventon-action-user/includes/admin/class-admin_lang.php(173): EVOAU_Lang->__construct() #1 {main} thrown in /users/laufgruppe-lvb/www/wordpress/wp-content/plugins/eventon-action-user/includes/admin/class-admin_lang.php on line 6