If you get a postcode invalid error when trying to create a shipping label with DX in the UK, please ensure that you have typed in the postcode correctly under the "Shipment Details" tab.
In this example, there was a comma that was inserted in the middle of the postcode by accident resulting in the failure of the order due to an invalid postcode.
Postcodes can be easily checked and verified with the website https://checkmypostcode.uk/
If there are any issues, please do not hesitate to contact our support team.