The developers of this app have not set up this app properly for Facebook Login

Error

App Not Setup: The developers of this app have not set up this app properly for Facebook Login.

Since the UI of the facebook has changed recently, here's the latest update for setting the sandbox mode ON/OFF :

1. Go to https://developers.facebook.com/

2. Click on the Apps menu on the top bar.

3. Select the respective app from the drop down.

4. Go to 'Status & Review' from the table in the left side of the page.

5. Do you want to make this app and all its live features available to the general public? - Select switch to set YES/NO value.