Which password do I need to use when setting up a connection via rclone?
You need to generate a new application-specific password in your Koofr web app to establish a connection to Koofr through rclone. See how to generate an application-specific password.
Note: Without an application-specific password, you will not be able to establish a connection between Koofr and rclone.
General note for using rclone with Koofr: Do not use --copy-links option with rclone when copying or syncing files to Koofr, since you might end up infinitely uploading your files over and over again if a cycle in the filesystem is induced by your symlinks or junction points.