DPD may return the message "Error trying to create consignment in DPD. Dpd said: Error code1021 - Service Denied".
You will first want to make sure the postcode in the shipment is valid, if it isn't then this would also cause the error.
If that doesn't work then the error may come up if you are attempting to send parcels on a service code that you do not have enabled to on your DPD account.
For example, if you tried to ship on the DPD Express - Document by Air service and saw the above message, this means that your DPD account is not setup to use DPD Express - Document by Air.
The service denied message is coming back directly from DPD, Shiptheory is unable to dispatch orders on your account for that specific service code you have attempted to use.
Please contact the DPD help desk on 0121 500 2510 or send them an email from here. and provide them the message exactly as above, along with the service code you have attempted to use and they should be able to advise the best course of action.
If in doubt, please get in touch with Shiptheory support and we will be happy to help where we can.