rclone config
n)new remotename? Dropboxdropboxclient_id> leave blankclient_secret> leave blankauto config? norclone authorize "dropbox"
paste the result in config_token
e.g
{"access_token":"XXX","token_type":"bearer","refresh_token":"XXX","expiry":"2023-05-13T16:15:51.875425+01:00"}
That's it...
rclone sync /home/pi/motion-images Dropbox:_pi/pi2-frontcamera