No longer get an error message when a candidate doesn't have an email address

Prior to enabling Redwood, in Recruiting if a candidate didn't have an email address a message would appear ‘The candidate can’t receive any messages because their preferred communication channel doesn’t exist’.

However, since enabling Redwood this message no longer appears and offer letters are being sent with no email address attached. Is there a way to have this message appear or is there a Redwood alternative?