Fatal error: Uncaught Error: Call to undefined function add_action() in /users/laufgruppe-lvb/www/wordpress/wp-content/plugins/eventon-bookings/includes/admin/class-admin_editor.php:19 Stack trace: #0 /users/laufgruppe-lvb/www/wordpress/wp-content/plugins/eventon-bookings/includes/admin/class-admin_editor.php(579): EVOBO_Admin_Editor->__construct() #1 {main} thrown in /users/laufgruppe-lvb/www/wordpress/wp-content/plugins/eventon-bookings/includes/admin/class-admin_editor.php on line 19