Appointments + Google Calendar API

For the life of me, I cannot get this plug in working. Every time I try to "generate my access code" I get this:
401. That’s an error.
Error: deleted_client
The OAuth client was deleted.

Request Details
access_type=offline
approval_prompt=auto
scope=https://www.googleapis.com/auth/calendar
response_type=code
redirect_uri=urn:ietf:wg:oauth:2.0:oob
client_id=XXXXXXXXXXXX-02khp8oqukv0mrlaoqr94qo1v9apcvtr.apps.googleusercontent.com
That’s all we know.

Please help!