In the Log around 400 I see this:
Beginning dispatch of backup to remote (googledrive)
0310.510 (1) Google Drive: requesting access token: client_id=(Removed)
0310.710 (1) Google Drive error when requesting access token: response does not contain access_token. Response: { "error" : "invalid_client"}
0310.712 (1) ERROR: Have not yet obtained an access token from Google (has the user authorised?)
0310.713 (1) An error condition has occurred for the first time during this job