An error which occours as soon as you want to proceed to the payment can have multiple causes:
- There where opened multiple browsers / tabs (the tickets you want to pay are no longer available because you have a new order in another browser / tab. Only one order per IP address can be valid)
- There was a problem connecting you to the bank / credit card company (due to a disturbance on their end)
Both causes unfortunately result in not being able to complete your order. Your tickets have already been or will be set available for sale again and are not being held. Ofcourse you can always try again.