When sending orders through from Magento 2 you may see some errors occur with the below message within your Shipment history. 

If you are unsure how to access your Shipment history locate the failed order, click View > Expand details > Scroll down to locate the shipment history for an order

If you see the error this means that your Magento server is running slow. Attempting to retry this order will push the order back through and often results in a successful booking. 

If after a few attempts it does not book, try to increase the resources on your Magento server and retry again.

Still not booking? Contact our support team who will be able to assist in diagnosing the problem.