The redirect URI in the request, https://www.scuolachannel.it/users/auth/google_oauth2/callback, does not match the ones authorized for the OAuth client. To update the authorized redirect URIs, visit: https://console.developers.google.com/apis/credentials/oauthclient/823208975411-a061a41gsipql08i18fnsgmhkta63hb1.apps.googleusercontent.com?project=823208975411