Hey @onetruck. This error is usually the result of trying to fetch or update an entity that doesn’t exist. In this case you may want to double check the order ID. The order ID is different from the order number, and can be found at the end of the URL when you open the order in Veeqo.
At the moment creating and buying labels isn’t possible through the API yet; only creating shipments. You could submit a feature request if you would like to see this functionality in the future.