I tried to generate a log file but it ran for hours without ever finishing. When I ran it overnight it gave the start 403 errors and then, as I said, failed with that error.
felix@gemini:~$ rclone size GD: -vv --fast-list
2021/11/18 13:46:02 DEBUG : Setting --config "/opt/rclone/rclone.conf" from environment variable RCLONE_CONFIG="/opt/rclone/rclone.conf"
2021/11/18 13:46:02 DEBUG : rclone: Version "v1.57.0" starting with parameters ["rclone" "size" "GD:" "-vv" "--fast-list"]
2021/11/18 13:46:02 DEBUG : Creating backend with remote "GD:"
2021/11/18 13:46:02 DEBUG : Using config file from "/opt/rclone/rclone.conf"
2021/11/18 13:46:04 DEBUG : Google drive root '': Disabling ListR to work around bug in drive as multi listing (4) returned no entries
2021/11/18 13:46:04 DEBUG : Google drive root '': Recycled 4 entries
2021/11/18 13:46:04 DEBUG : Google drive root '': Recycled 5 entries
2021/11/18 13:46:04 DEBUG : pacer: low level retry 1/10 (error googleapi: Error 403: User Rate Limit Exceeded. Rate of requests for user exceed configured project quota. You may consider re-evaluating expected per-user traffic to the API and adjust project quota limits accordingly. You may monitor aggregate quota usage and adjust limits in the API Console: https://console.developers.google.com/apis/api/drive.googleapis.com/quotas?project=286927808882, userRateLimitExceeded)
2021/11/18 13:46:04 DEBUG : pacer: Rate limited, increasing sleep to 1.060685089s
2021/11/18 13:46:04 DEBUG : pacer: Reducing sleep to 0s