Facebook Authentication failing to pop up

Using the Facebook JavaScript SDK for authentication things have recently changed to OAuth 2.0.

Calls to FB.getLoginStatus are now different.

Old Method

FB.getLoginStatus(function(response) {
if (response.authResponse) {
// logged in and connected user, someone you know

} else {

New Method

FB.getLoginStatus(function(response) {
if (response.status === 'connected') {
// the user is logged in and connected to your
// app, and response.authResponse supplies
// the user's ID, a valid access token, a signed
// request, and the time the access token
// and signed request each expire
var uid = response.authResponse.userID;
var accessToken = response.authResponse.accessToken;
} else if (response.status === 'not_authorized') {
// the user is logged in to Facebook,
//but not connected to the app
} else {
// the user isn't even logged in to Facebook.