To send messages to Flipkey guests, their email address must be included in the reservation details. If email details are not relayed, you can ask your Flipkey account manager to activate this option for your channel management connection.
The Hostaway software allows you to send out emails to the guests and receive the replies from the guests in the Hostaway software. Emails and messages sent by the guests that are not a reply to an email and sent within the Flipkey portal, will not be received in the Hostaway software.