In order to start seeing Quotes for DPD services and to be able to print labels for them, the following setting would need to be enabled:
Linnworks.net > Shipping > Integrations > Amazon - Buy Shipping > Config > Quote > Delivery Confirmation with Signature:
Also, you would need to make sure that DPD Terms and conditions have been accepted via https://sellercentral.amazon.co.uk/gp/shipping-manager/terms-and-conditions.html
If the order will have correct weight and dimensions assigned, the DPD label will be requested and printed successfully.
NB! Amazon will require customers to print DPD labels in ZPL format, which can be enabled via Linnworks.net > Shipping > Integrations > Printer > Template > ZPL