So without any actual data, I’d guess you are hitting the daily limits without seeing any scripts/logs or knowing how much you transferred.
It seems it’s the other owner that is hitting daily limits as I’m unable to do any copies directly using google drive website. I’ve not tried using the google backup and sync.
That makes sense. Are you able to see the other API hits?
Erm do you mean the API for the owner of the other google drive/suite account? If so no I’m not able to see them.