Google Oauth2 Response_type Error On Authorization Code Request

I'm trying to get an authorization code from Google+ API, as described in Step 1(Set authorization parameters) (HTTP/REST). As I've read there, the Google authorization server has

Solution 1:

Since you're following the server documentation, the response_type=code parameter is present in the sample authorization request URL in the next step [1].

You can learn more about response types here: https://developers.google.com/identity/protocols/OpenIDConnect#response-type

[1] https://developers.google.com/identity/protocols/OAuth2WebServer#redirecting