how to debug facebook app/django setup (url is not valid...)

I'm trying to set up a facebook app using开发者_JAVA技巧 django by following this tutorial: http://www.rkblog.rk.edu.pl/w/p/example-facebook-application-django/ . I get to the point where I start my development server at (manage.py runserver 0.0.0.0:80)

then it says: Now under http://apps.facebook.com/NAME/ you should see a basic Facebook app comming from your server:

I, however, get an error message:

The URL http://my.ip/my_app_name/ is not valid.

I think I've set things up properly:

Canvas Page URL: http://apps.facebook.com/my_app_name/

Canvas Callback URL http://my.ip/my_app_name/

Question: how do I go about finding out what's wrong?

Thanks in advance!

Martin

update: when i visit http://my.ip/myappname/, it redirects to http://apps.facebook.com/my_app_name/?auth_token=eac7bf38fb5e591c55ddc458d16dc9b7

where i get the 'url not valid' message... However, when I paste the url with auth_token in it, django serves the requested page as expected... why is facebook saying the url is not valid if in fact it is...?

Is your router set up to forward requests on port 80 to your development machine? If not, you will get an error, as the way Facebook apps work is that Facebook's servers contact your server, get the content, then parse it and re-serve it back to the client.

I actually find with Facebook apps that the easiest thing to do is what you describe in your last sentence - get the auth_token URL, then paste it locally and work from there.