Fatal error: Uncaught Error: Call to undefined function add_filter() in /home/workings/public_html/hidden/wp-content/plugins/fusion-core/shortcodes/class-countdown.php:13 Stack trace: #0 /home/workings/public_html/hidden/wp-content/plugins/fusion-core/shortcodes/class-countdown.php(214): FusionSC_Countdown->__construct() #1 {main} thrown in /home/workings/public_html/hidden/wp-content/plugins/fusion-core/shortcodes/class-countdown.php on line 13