Fatal error: Uncaught Error: Call to undefined function add_action() in /opt/app-root/src/wp-content/plugins/advanced-custom-fields/includes/admin/admin-field-groups.php:38 Stack trace: #0 /opt/app-root/src/wp-content/plugins/advanced-custom-fields/includes/admin/admin-field-groups.php(826): acf_admin_field_groups->__construct() #1 {main} thrown in /opt/app-root/src/wp-content/plugins/advanced-custom-fields/includes/admin/admin-field-groups.php on line 38