Fatal error: Uncaught Error: Call to undefined function add_action() in /home/clmepl5/public_html/web/app/plugins/relevanssi/lib/compatibility/product-gtin-ean-upc-isbn-for-woocommerce.php:13 Stack trace: #0 {main} thrown in /home/clmepl5/public_html/web/app/plugins/relevanssi/lib/compatibility/product-gtin-ean-upc-isbn-for-woocommerce.php on line 13