NotAllowedError on front main page '/'

Question

I tried to set the Main Page '/' for users to login or not login, but I get a NotAllowedError. This works in the local server. However, it does not seem to work in the real public server.

Does NotAllowedError mean complying to Google App Engine standards of not putting a login on the front page or maybe its something else?

Here is the error:

Traceback (most recent call last):
  File "/base/data/home/runtimes/python27/python27_lib/versions/third_party/webapp2-2.5.2/webapp2.py", line 1535, in __call__
    rv = self.handle_exception(request, response, e)
  File "/base/data/home/runtimes/python27/python27_lib/versions/third_party/webapp2-2.5.2/webapp2.py", line 1529, in __call__
    rv = self.router.dispatch(request, response)
  File "/base/data/home/runtimes/python27/python27_lib/versions/third_party/webapp2-2.5.2/webapp2.py", line 1278, in default_dispatcher
    return route.handler_adapter(request, response)
  File "/base/data/home/runtimes/python27/python27_lib/versions/third_party/webapp2-2.5.2/webapp2.py", line 1102, in __call__
    return handler.dispatch()
  File "/base/data/home/runtimes/python27/python27_lib/versions/third_party/webapp2-2.5.2/webapp2.py", line 572, in dispatch
    return self.handle_exception(e, self.app.debug)
  File "/base/data/home/runtimes/python27/python27_lib/versions/third_party/webapp2-2.5.2/webapp2.py", line 570, in dispatch
    return method(*args, **kwargs)
  File "/base/data/home/apps/s~map-jobs/2.371277816538602179/main.py", line 294, in get
    user_url = users.create_login_url() # raise NotAllowedError
  File "/base/data/home/runtimes/python27/python27_lib/versions/1/google/appengine/api/users.py", line 256, in create_login_url
    raise NotAllowedError
NotAllowedError

Here is my MainHandler:

class MainHandler(BaseHandler):
  def get(self):
    user = users.get_current_user()
    logout_url = users.create_logout_url(self.request.uri)
    profile=''
    if user:
      profile = Profile.query(Profile.user_id==user.user_id())
      if profile.count() <= 0:
        profile = Profile()
        profile.user_id = user.user_id()
        profile.email = user.email()
        profile.firstname = user.nickname()
        profile_key = profile.put()
      else:
        profile_key = Profile.query(Profile.user_id==user.user_id())
      profile = profile_key.get()
      current_user = 'Hello, '+ user.nickname()
      user_url = logout_url
      title = "Click to logout from Google."
    else:
      current_user = 'Google Sign in'
      user_url = users.create_login_url(self.request.uri) # raise NotAllowedError
      title = "Click to sign in with your Google Account."
    values = {
      'current_user' : current_user,
      'user_url' : user_url,
      'profile' : profile,
    }
    self.render_html('index.html',values)

Here is part of my webapp2.WSGIApplication:

app = webapp2.WSGIApplication([
  ('/', MainHandler),
], debug=True)

Here is my app.yaml:

application: map-jobs
version: 2
runtime: python27
api_version: 1
threadsafe: yes

handlers:
- url: /favicon\.ico
  static_files: favicon.ico
  upload: favicon\.ico

- url: /(.*\.(gif|png|jpg|js|css|woff|ttf|svg))
  static_files: static/\1
  upload: static/(.*\.(gif|png|jpg|js|css|woff|ttf|svg))

- url: /templates/.*
  script: templates.app

- url: .*
  script: main.app


libraries:
- name: webapp2
  version: "2.5.2"

- name: jinja2
  version: "2.6"

Answer 1

Never mind, I just made a mistake. I should use Google Accounts API instead of Google Apps Domain in my Application settings.