Support for proton drive on rclone is still on beta [1], Proton, AFAIK, doesn't provide documented official APIs for accessing their Drive. Much of the work on the rclone plugin was made via reverse engineering and reading Proton's open source projects code

[1]: https://rclone.org/protondrive/

My rclone for proton stopped working this week and I just cannot get it working. It's looking likely the support will be dropped as the dev is no longer working on it and it's not finished.

Hopefully proton will hurry up with their SDK. Through the rclone GUI I can access and mount the folders and files but I cannot get any auto rclone commands to actually transfer any files.

They are working on an SDK, which they will use for their own Linux client: https://proton.me/blog/proton-drive-sdk-preview