 Error: Authorization Required when calling POST /FBUsers/login-facebook using explorer

Hi
I did 'git clone' this sample app. then got (hopefully correct) OAuth2 token from facebook. and called 'login-facebook'

But I get following exception.

Error: Authorization Required
    at D:\Projects\LoopBack\custom-facebook-auth\node_modules\loopback\lib\application.js:392:21

Please advice what may be wrong.