Trouble approving API Authentification for JSON Rest API

When I try to get an access token to be able to get my sites stats via REST API, the following error message appears:
“That site does not seem to be accessible or no longer has the Jetpack Plug In installed”

Jetpack is installed an runs on latest version. I disabled other critical Plug-Ins and tried again but got the same error.
I use this link to try to grant access:
https://public-api.wordpress.com/oauth2/authorize?client_id=<my_client_id>&redirect_uri=<my_redirect_url>&response_type=token

Is there any way to fix this issue?

The page I need help with: [log in to see the link]