Fatal error: Uncaught Error: Call to undefined function add_filter() in /var/www/blues/wp-content/plugins/events-manager/classes/em-permalinks.php:18 Stack trace: #0 /var/www/blues/wp-content/plugins/events-manager/classes/em-permalinks.php(287): EM_Permalinks::init() #1 {main} thrown in /var/www/blues/wp-content/plugins/events-manager/classes/em-permalinks.php on line 18