Gutenberg Test Add Heading Fatal error: Uncaught TypeError: call_user_func_array(): Argument #1 ($callback) must be a valid callback, function "cartify_woocommerce_products_loop_category_title" not found or invalid function name in /home/postcard/domains/postcardshop4u.com/public_html/wp-includes/class-wp-hook.php:324 Stack trace: #0 /home/postcard/domains/postcardshop4u.com/public_html/wp-includes/class-wp-hook.php(348): WP_Hook->apply_filters() #1 /home/postcard/domains/postcardshop4u.com/public_html/wp-includes/plugin.php(517): WP_Hook->do_action() #2 /home/postcard/domains/postcardshop4u.com/public_html/wp-content/plugins/woocommerce/templates/content-product.php(49): do_action() #3 /home/postcard/domains/postcardshop4u.com/public_html/wp-includes/template.php(812): require('/home/postcard/...') #4 /home/postcard/domains/postcardshop4u.com/public_html/wp-content/plugins/woocommerce/includes/wc-core-functions.php(284): load_template() #5 /home/postcard/domains/postcardshop4u.com/public_html/wp-content/plugins/agni-builder/gutenberg-blocks/blocks/products.php(270): wc_get_template_part() #6 /home/postcard/domains/postcardshop4u.com/public_html/wp-includes/class-wp-block.php(519): dynamic_blocks_agni_products() #7 /home/postcard/domains/postcardshop4u.com/public_html/wp-includes/blocks.php(2061): WP_Block->render() #8 /home/postcard/domains/postcardshop4u.com/public_html/wp-includes/blocks.php(2113): render_block() #9 /home/postcard/domains/postcardshop4u.com/public_html/wp-includes/class-wp-hook.php(324): do_blocks() #10 /home/postcard/domains/postcardshop4u.com/public_html/wp-includes/plugin.php(205): WP_Hook->apply_filters() #11 /home/postcard/domains/postcardshop4u.com/public_html/wp-includes/post-template.php(256): apply_filters() #12 /home/postcard/domains/postcardshop4u.com/public_html/wp-content/themes/storefront/inc/storefront-template-functions.php(352): the_content() #13 /home/postcard/domains/postcardshop4u.com/public_html/wp-includes/class-wp-hook.php(324): storefront_page_content() #14 /home/postcard/domains/postcardshop4u.com/public_html/wp-includes/class-wp-hook.php(348): WP_Hook->apply_filters() #15 /home/postcard/domains/postcardshop4u.com/public_html/wp-includes/plugin.php(517): WP_Hook->do_action() #16 /home/postcard/domains/postcardshop4u.com/public_html/wp-content/themes/storefront/content-page.php(18): do_action() #17 /home/postcard/domains/postcardshop4u.com/public_html/wp-includes/template.php(812): require('/home/postcard/...') #18 /home/postcard/domains/postcardshop4u.com/public_html/wp-includes/template.php(745): load_template() #19 /home/postcard/domains/postcardshop4u.com/public_html/wp-includes/general-template.php(206): locate_template() #20 /home/postcard/domains/postcardshop4u.com/public_html/wp-content/themes/storefront/page.php(24): get_template_part() #21 /home/postcard/domains/postcardshop4u.com/public_html/wp-includes/template-loader.php(106): include('/home/postcard/...') #22 /home/postcard/domains/postcardshop4u.com/public_html/wp-blog-header.php(19): require_once('/home/postcard/...') #23 /home/postcard/domains/postcardshop4u.com/public_html/index.php(17): require('/home/postcard/...') #24 {main} thrown in /home/postcard/domains/postcardshop4u.com/public_html/wp-includes/class-wp-hook.php on line 324