Ensure ‘Enable backup rsync service’ is enabled in your Ugreen Control Panel, and select an existing user that will be used when transferring with rsync:

To rsync a local folder to your Ugreen NAS, use:
rsync -avz ./local-folder/ user-enabled-for-rsync@your-ugreen-ip:NAME_OF_SHARE
Note that instead of using the path of a folder on a volume, e.g. /volume1/folder
, if folder
is the name of the share, use this as the target path without any absolete path prefix.
This is hinted at in this post, and while it seems to differ from how you’d normally specify a remote destination, this is how rsync on a Ugreen appears to work.