You will find settings for error handling on the last tab of the Flow Engine Queue Treatment page. You can choose how the treatment behaves in the event of an error during the voicemail or callback processes. You can choose to keep the caller in queue and restart the queue treatment, or you can disconnect. In either case you can play an error message. You will also find a place on this tab to set an “Invalid Input” message. This message will be played if there’s an error on any input, and a retry is necessary.