Fatal error: Uncaught Error: Call to undefined function Automattic\Jetpack\Assets\wp_is_serving_rest_request() in /var/www/clients/client38/web172/web/wp-content/plugins/woocommerce-direct-checkout/jetpack_vendor/automattic/jetpack-assets/src/class-script-data.php:113 Stack trace: #0 /var/www/clients/client38/web172/web/wp-content/plugins/woocommerce-direct-checkout/jetpack_vendor/automattic/jetpack-assets/src/class-script-data.php(88): Automattic\Jetpack\Assets\Script_Data::is_authenticated_rest_request() #1 /var/www/clients/client38/web172/web/wp-includes/class-wp-hook.php(308): Automattic\Jetpack\Assets\Script_Data::render_script_data('') #2 /var/www/clients/client38/web172/web/wp-includes/class-wp-hook.php(332): WP_Hook->apply_filters('', Array) #3 /var/www/clients/client38/web172/web/wp-includes/plugin.php(517): WP_Hook->do_action(Array) #4 /var/www/clients/client38/web172/web/wp-includes/script-loader.php(2146): do_action('wp_print_script...') #5 /var/www/clients/client38/web172/web/wp-includes/class-wp-hook.php(308): wp_print_head_scripts('') #6 /var/www/clients/client38/web172/web/wp-includes/class-wp-hook.php(332): WP_Hook->apply_filters(Array, Array) #7 /var/www/clients/client38/web172/web/wp-includes/plugin.php(517): WP_Hook->do_action(Array) #8 /var/www/clients/client38/web172/web/wp-includes/general-template.php(3049): do_action('wp_head') #9 /var/www/clients/client38/web172/web/wp-content/themes/danf/header.php(69): wp_head() #10 /var/www/clients/client38/web172/web/wp-includes/template.php(783): require_once('/var/www/client...') #11 /var/www/clients/client38/web172/web/wp-includes/template.php(718): load_template('/var/www/client...', true, Array) #12 /var/www/clients/client38/web172/web/wp-includes/general-template.php(48): locate_template(Array, true, true, Array) #13 /var/www/clients/client38/web172/web/wp-content/themes/danf/index.php(3): get_header() #14 /var/www/clients/client38/web172/web/wp-includes/template-loader.php(106): include('/var/www/client...') #15 /var/www/clients/client38/web172/web/wp-blog-header.php(19): require_once('/var/www/client...') #16 /var/www/clients/client38/web172/web/index.php(17): require('/var/www/client...') #17 {main} thrown in /var/www/clients/client38/web172/web/wp-content/plugins/woocommerce-direct-checkout/jetpack_vendor/automattic/jetpack-assets/src/class-script-data.php on line 113