Fatal error: Uncaught Error: Call to undefined function add_filter() in /users/laufgruppe-lvb/www/wordpress/wp-content/plugins/eventon-action-user-plus/includes/class-shortcode.php:10 Stack trace: #0 /users/laufgruppe-lvb/www/wordpress/wp-content/plugins/eventon-action-user-plus/includes/class-shortcode.php(120): aup_shortcode->__construct() #1 {main} thrown in /users/laufgruppe-lvb/www/wordpress/wp-content/plugins/eventon-action-user-plus/includes/class-shortcode.php on line 10