Facebook is undefined

I have upgraded my working Ionic 2 app to Ionic 3 and Ionic Native 3.
For some reason the facebook object that I receive in constructor is undefined:

  1. ionic plugin add cordova-plugin-facebook4 --variable APP_ID=“123456789” --variable APP_NAME=“myApplication”
  2. npm install --save @ionic-native/facebook
  3. @NgModule({ … providers: [ Facebook ] … })
  4. import { Facebook, FacebookLoginResponse } from ‘@ionic-native/facebook’;
  5. constructor(private facebook:Facebook) {}

The facebook parameter is undefined…

Can you post the exact error you are getting?