Request confirmation form missing

[mike14]

Hello Everyone

According to this manual 

https://canvas.instructure.com/doc/api/file.oauth.html

1) Step 1: Redirect users to request Canvas access
It is okay

2) Step 2: Redirect back to the request_uri, or out-of-band redirect
If the user accepts your request, Canvas redirects back to your request_uri with a specific query string, containing the OAuth2 response

I have issue on this step. As I understand Canvas should show form for acceptiong.

But I do not see this form and Canvas redirect me to my request url immediately.

There are not code parameter in redirect url.

My question

Why did accepting form disappear ?