The insta-auth example does not seem to work anymore.

### How to reproduce these conditions

**popup.html does not close and does not redirect**

**Steps to set up and reproduce:
Open the demo at https://instagram-auth.appspot.com/
Click on SIGN IN WITH INSTAGRAM button which will led to /popup.html
Enter your instagram credentials.
Gets stuck at "Waiting for instagram-auth.appspot.com"**

### Expected behavior
Popup should close and the example should show logged in user's details.

### Actual behavior
Popup never closes. Tested in Safari and Chrome.