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Some setup you must do manually if you haven't yet:
1. Ensure you have overridden or uncommented the routes for generated omniauth callback controllers in your routes.rb. For example: Rails.application.routes.draw do devise_for :users, controllers: { omniauth_callbacks: "users/omniauth_callbacks" } end 2. Update the devise facebook omniauth APP_ID and APP_SECRET in "config/initializers/devise.rb" after registering the Rails application on: https://developers.facebook.com/apps/ For example: config.omniauth :facebook, "APP_ID", "APP_SECRET" 3. Your omniauth callback URL will be: `<host>/users/auth/facebook/callback`. Please update callback URL in Facebook after registering your omniauth application.