Fatal error: Uncaught Error: Call to undefined method WooCommerce::add_error() in /homepages/40/d207835591/htdocs/iustrings/wp-content/plugins/woocommerce-product-addons/product-addons.php:742 Stack trace: #0 /homepages/40/d207835591/htdocs/iustrings/wp-includes/class-wp-hook.php(298): woocommerce_product_addons->validate_add_cart_item(false, 1223, 1) #1 /homepages/40/d207835591/htdocs/iustrings/wp-includes/plugin.php(203): WP_Hook->apply_filters(true, Array) #2 /homepages/40/d207835591/htdocs/iustrings/wp-content/plugins/woocommerce/includes/class-wc-form-handler.php(640): apply_filters('woocommerce_add...', true, 1223, 1) #3 /homepages/40/d207835591/htdocs/iustrings/wp-content/plugins/woocommerce/includes/class-wc-form-handler.php(616): WC_Form_Handler::add_to_cart_handler_simple(1223) #4 /homepages/40/d207835591/htdocs/iustrings/wp-includes/class-wp-hook.php(298): WC_Form_Handler::add_to_cart_action('') #5 /homepages/40/d207835591/htdocs/iustrings/wp-includes/class-wp-hook.php(323): WP_Hook->apply_filters(NULL, Array) in /homepages/40/d207835591/htdocs/iustrings/wp-content/plugins/woocommerce-product-addons/product-addons.php on line 742