I have tried printing a TNT shipping label and am seeing an error returned:
562: The receiver address town postcode combination is invalid
Please review if the order has correct values in the shipping address fields. This error is usually returned when order postcode and town field do not match. It can be also returned when town and postcode fields are incorrectly spelled.
You can amend/check the Shipping Address in Linnworks.net > Orders > Open Orders screen, when you Edit the order.
Shipping - Get Quotes is not producing any/expected services