Have you tried following the instructions that should be being displayed in the config node ?
"It appears you are running on a private IP address that the Google service cannot reach. Please configure the authorized Redirect URIs of your app to include the following url:
http://node-red.example.com:1880/google-credentials/auth/callback
You will need to edit your hosts file and add an entry for
node-red.example.com that points to <your local ip address> .
You also need to enable the Google+ API for your new project in the Google Developers Console."