Snapshot not working with Google Drive

I've followed the instructions for setting up an API for Google Drive and everything looked great. I ran a backup and it LOOKED as if it was successful (showed the date and time of the last backup and even the size of the file), but then I noticed "1 Fail" on the All Snapshots page. No reason for the backup failing, so I can't troubleshoot.

Can you help? I'm going to grant access to the site for support.