I have tried printing a shipping label and am seeing an error returned:
Print labels: xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx, Consignments: 1, Error: The remote server returned an unexpected response: (400) Bad Request.
This error usually appears if there is an unsupported symbol or character somewhere in the order details. You can go to Linnworks.net > Order > Open Orders screen and View the order or Edit it and see if there are any unusual symbols, characters or long spaces in the order's Shipping or Billing Address section.
You can also check if any of the order items have them in their titles or customs descriptions in Inventory > My Inventory > Product Details > Extended Properties section.
If all of the above details seem correct, please contact Linnworks support for further assistance.
Product Details: Extended Properties