Hi Elizabeth,
There is not a solution within Yale for the terrible message they send to the guest. My solution was to use Guesty For Hosts to manage my listings and to take care of the messaging. They have a very nice integration with Yale that automatically creates codes for the guest and you can send in an automated message (fully customizable to you). It’s about $35/mo per property but I’m super happy with it. You can even see other info about your locks such as battery life in the Guesty Locks Manager, which you can’t see in the Yale app. There may be other ways to do this but this has been a success for me.
hope that helps!
Adam