If you are getting the following error message (ErrorMessage: The remote server returned an error: (500) Internal Server Error.) from DPD it can be down to the system timing out when trying to obtain the courier label. Causes for the system timing out can be related to:
The Weight of the parcel is too much for the courier to handle.
The number of Parcels doesn't add up to the number of Items on the order.
DPD are facing an outage which will affect customers trying to generate labels.