Why do I get the error "IOSS number specified for non IOSS service. Please change the shipping method on the order."?

Overview

This error occurs when you try to despatch an order where EU VAT was collected by the marketplace, but the selected Royal Mail shipping service does not support IOSS.

Cause

Since July 2021, EU VAT rules require that the marketplace's IOSS number be included in the data sent to the courier when creating a label for orders where VAT was collected at point of sale (for example, via eBay or Amazon).

This error means you are using a Royal Mail service that is not one of the designated IOSS-compatible "core services". Since February/March 2021, Royal Mail has advised senders to switch international services to core services to handle IOSS orders correctly.

Solution

Go to Settings > Shipping Configuration > Shipping Methods and update the service codes on your international shipping methods to use one of the Royal Mail core services shown below:

For more information on Royal Mail IOSS requirements, see the Royal Mail IOSS FAQs at https://www.royalmail.com/business/international/guide/delivered-duties-paid/ioss-faqs.

See "Creating a Shipping Method" for guidance on updating your shipping method service codes.