Oauth/request_token returns 404 page not found


I am trying to implement ‘Sign in with Twitter’ as instructed on https://dev.twitter.com/docs/auth/implementing-sign-twitter

For some reason the service returns 404 page not found.

If I test oauth with the ‘Test OAuth’ button on my app page, I get the same result. The api address I use is https://api.twitter.com/1.1/oauth/request_token, the request method is POST and the request query contains a value for oauth_callback. When I execute the curl command produced, I still get 404 page not found.

What could be wrong? I have enabled my app for ‘Sign in with Twitter’.

Thanks in advance,