I have followed the instructions here:
The developers of this app have not set up this app properly for Facebook Login?
Made my app public and the circle is
I had the same problem and it took me around one hour to figure out where i went wrong only to note that i had used a wrong app id....just go to your code and used a correct id here
window.fbAsyncInit = function() {
FB.init({
appId : '1740077446229063',//your app id
cookie : true, // enable cookies to allow the server to access
// the session
xfbml : true, // parse social plugins on this page
version : 'v2.5' // use graph api version 2.5
});