Realize Google AppInvite
by Google
manual - link.
Start Invite Activity
and get next in the LogCat:
E/AppInvit
I think that it should work automatically, if you have connected your Firebase with your app on Google Play, but you have to download your application from Google Play. I had the same problem and it didn't work in my case, because I had the version of an application which I installed straight from the computer (debug mode).