Important note: If you first experience this issue while processing a sale in the POS, you will not be able to reconnect the payment using the resolve bar once you've gone through these steps. Please void the original ticket and recreate the sale on a new ticket.
On the Dejavoo Z9, you should be at the POS Online screen. Press ok (green button), it will ask you for a manager password, enter 1234, then press ok.
You should now be on the Core Menu, select Applications, select Credit/Debit/EBT, select Host Utility, then reenter the manager password and press ok.
Scroll down to the bottom and select Mercury Features, choose Vantiv Features on the next screen, then select Delete Reversal Msg.
The Dejavoo device will ask if you're sure, choose yes.
Once it loads back to the Vantiv Features screen you can press the red X button until you're back at the POS Online screen. You should be all set to retry the sale from a new ticket!
If this still does not fix the issue, please call Dejavoo at (877) 358-6797 and they will be able to assist you further.