When shipping with DHL internationally, the following error may occure if your Duty Account Number is incorrect.

Unable to create label The system could not verify your billing account number. Please enter another account and resubmit.For assistance call DHL customer services.

Check that your Duty Account Number is correct and matches your DHL account. You can set your Duty Account Number from the advanced section of the DHL edit page within Shiptheory, as shown below.