I have tried printing a Deutsche Post shipping label and am seeing an error returned:

items[0].contents[0].contentPieceOrigin: size must be 2 characters


The error is being returned because there is an incorrect Item Extended Property value for Country of Origin on an order item. ISO-2 codes need to be supplied as those are expected instead of using full country names. If there is no property present on the item, then default values will be checked from > Shipping > Integrations > Services > Edit screen or from > Shipping > Config in Linnworks.

Related articles:

Shipping - HS Tariff Code and Country of Origin