The error (Error: Tried to generate a Royal Mail label, but the provided combination of service, destination country code, postcode, and class is invalid for the specified destination. Please correct and try again.) from Royal Mail typically occurs when attempting to ship orders to Isle of Man, or one of the Channel Islands (Like Jersey or Guernsey) using United Kingdom as the country code.
These locations require specific country codes to generate Royal Mail labels correctly. To resolve this issue please review the steps below:
Click Settings then Countries.
Ensure the following countries are set up with the correct codes:
Country: Isle of Man Code: IM Code3: IOM
Country: Jersey Code: JE Code3: JEY
Country: Guernsey Code: GG Code3: GGY
Ensure orders destined for these locations include the correct country in the country field.
Note: UNITED KINGDOM will not work for Royal Mail orders to these destinations. For detailed instructions on setting up custom countries, refer to: Shipping Management - Create a custom country.
By following these steps, you should be able to resolve the error.