Hello @essie
Thank you for your request.
All error messages with DTR mean Datatrans, our partner for payment card processing. The error message can occur when buying a ticket or entering the payment card and means that the billing process is currently not working.
You can try to delete the app and reinstall it. After that, I recommend you to delete the stored data first before saving a new payment method.
If the card is not saved, please contact the card issuer.
Have a great day, SandrineS