Label error — DPD UK — Synkka Print Label API 422

DPD UK label error via Synkka caused by an unsupported return route, most commonly a customer address in Northern Ireland. Learn how to resolve it.

1 min readUpdated Oct 1, 2026

This error occurs when DPD UK cannot create a Synkka return label, usually because the customer's address is in Northern Ireland, which is not supported for DPD returns through this integration.

Error message

"Failed to create Synkka shipping label: Synkka Print Label API Error 422: Unprocessable Entity"

What this means

DPD UK does not support returns from Northern Ireland through the Synkka integration.

How to fix it

  1. Open the RMA.
  2. Check whether the customer's return address is in Northern Ireland.
  3. If it is, change the carrier to Royal Mail.
  4. Regenerate the label.

If the issue continues

Contact support with the RMA ID, customer address, and a screenshot of the error.