Need Facebook app domain auth for User Account UI, but Facebook rejecting Android/iOS app market domains

I have been trying to deploy an app that uses Facebook as a login system. However the on my app the login for Facebook is not there ( I am using user accounts ui). I am assuming it is because the domain for my app is not listed in Facebook.

When I try to register play.google.com or google.com in general, Facebook rejects it. Any ideas? It says “App domains must match the domain of the Secure Canvas URL, Mobile Site URL, Unity Binary URL, Site URL or Secure Page Tab URL. Please correct these domains: google.com

I think you are not following the steps correctly. A very good tutorial @ https://themeteorchef.com/recipes/roll-your-own-authentication/

If you follow the steps, it works.