The cart is empty after redirect to the cancel_url

-- url of the page with the problem -- : http://localhost/joomla/index.php?option=com_hikashop&ctrl=order&task=cancel_order&order_id=105&Itemid=515
-- HikaShop version -- : 2.6.3
-- Joomla version -- : 3.5.1
-- PHP version -- : 5.6.14

Hi,
My payment gateway doesn't send a notification request, but passes the information to the return URL. So I use notification URL as return URL and redirect the user to the HikaShop return URL at the end of the onPaymentNotification function. Same with the cancel URL. But in my case if the buyer cancels the payment on the payment gateway, the order status changes to "cancelled" but the user is not returned on the checkout, instead, the page opens with the list of products (http://xxx/index.php/product/listing) and message "The cart is empty".
Please help to understand what's wrong.

$cancel_url = HIKASHOP_LIVE . 'index.php?option=com_hikashop&ctrl=order&task=cancel_order&order_id=' . $order_id . '&lang='.$this->locale. $this->url_itemid;

Yes, you are right.
Thank you very much