I'm trying to make login with Facebook available in my script. I've done everything, but when I attempt to login with a Facebook account I get this error from Facebook:
App Not Setup: The developers of this app have not set up this app properly for Facebook Login.
With respect to the all the other answers, here's the screenshot to help someone.
The circle next to your app name is not fully green. When you hover mouse on it, you'll see a popup saying, "Not available to all users because your app is not live."
So next, you've to make it publicly available.