Order fulfillment 406 response

[dherbs2]

Hi, We haven't been using this for a while, but now when we're using the order fulfillment method we're getting 406. It used to work just fine before.

PHP Fatal error: Uncaught PHPShopify\Exception\CurlException: Request failed with HTTP Code 406. in /libs/vendor/phpclassic/php-shopify/lib/ShopifyResource.php:544

$data = array( "fulfillment" => array( "tracking_company" => $tracking_company, "tracking_number" => $shipping_tracking_number, "notify_customer" => false ) );

Array ( [fulfillment] => Array ( [tracking_company] => USPS [tracking_number] => 943461690148539231**** [notify_customer] => ) ) $shopify_id = 5536948387889; $result = $shopify->Order($shopify_id)->Fulfillment->post($data);

The other methods we're using work just fine.

Please advise! Thanks!