Fatal error: Uncaught Error: Call to undefined function wp_nonce_field() in /home/www/sieml/wp-content/plugins/the-events-calendar/src/admin-views/metabox/compatibility/events-control-extension/mark-online.php:26 Stack trace: #0 {main} thrown in /home/www/sieml/wp-content/plugins/the-events-calendar/src/admin-views/metabox/compatibility/events-control-extension/mark-online.php on line 26