Fatal error: Uncaught Error: Call to undefined function add_filter() in /home/cleangre/public_html/wp-content/plugins/woocommerce/includes/class-wc-brands-coupons.php:21 Stack trace: #0 /home/cleangre/public_html/wp-content/plugins/woocommerce/includes/class-wc-brands-coupons.php(189): WC_Brands_Coupons->__construct() #1 {main} thrown in /home/cleangre/public_html/wp-content/plugins/woocommerce/includes/class-wc-brands-coupons.php on line 21