python Flask-oauth with facebook is throwing a webpage not found error -

i trying authenticate user using facebook oauth throwing webpage not found error after user allows app in facebook.

here's code:

from flask import redirect, flask, url_for, request  app = flask(__name__) app.secret_key = 'asd'  oauth = oauth() facebook = oauth.remote_app('facebook',     base_url='https://graph.facebook.com/',     request_token_url=none,     access_token_url='/oauth/access_token',     authorize_url='https://www.facebook.com/dialog/oauth',     consumer_key='xxx',     consumer_secret='yyy',     request_token_params={'scope': 'email'} )  @app.route('/login') def login():     print(url_for('oauth_authorized'))     return facebook.authorize(callback='www.resoorce.com' + url_for('oauth_authorized'))  @app.route('/oauth_authorized') @facebook.authorized_handler def oauth_authorized(resp):     print("asd")     if resp none:         print(u'you denied request sign in.')         return "noooo"        print('you signed in %s' % resp['screen_name'])     return "yeah!!!"   if(__name__ == "__main__"):     app.debug = true;     app.run(hostname = '0.0.0.0', port=int(80)) 

no error thrown anywhere, webpage not found.