DPD restricts the time you have to print a label. You may not be able to print a label if the dispatch date has already passed or if the manifest has already been finalised.
If you try to print a label under these conditions or if you have deleted the shipment from your Interlink account you may see the error Could not create Interlink label. DPD error code: 1006 : The requested resource is not available for updating.
The error message is coming back directly from DPD, Shiptheory is unable to print this label. Please login to your DPD account to access this label directly.
The second option is to re-book the failed shipment in Shiptheory, this will regenerate the label and should circumvent this issue.