If an order didn't show on the KDS screen but was sent to the printer, check the Ticket Display Options on the KDS. learn more: Get Help With KDS Tickets.
If an order didn't send to the printer and it didn't show on the KDS screen, check that the items in the order are routed to the correct prep station.
You can also check item routing rules to ensure that the item isn't being unintentionally redirected. Learn more: .
If you use device groups, check to make sure that the devices in question are all part of the same group. Learn more: .