Using RsyncUI to synchronise data to a remote server requires what is called passwordless login by ssh-key. It is not possible to supply a user login and password in progress of synchronize data in RsyncUI. Before commencing to use RsyncUI to synchronize data to a remote server, it is required to setup and enable passwordless login by ssh-key. It is recommended to setup and enable this by terminal before using RsyncUI....
RsyncUI does not support a rsync daemon setup. Passwordless connections is by ssh-keys. But you might get it to work by following this guide. With a few tweaks it is possible to get RsyncUI working with rsync daemon. Be aware of not utilizing ssh, transfer of data is not encrypted. This is might not a problem on a local network, but I would not advise it on a public network. Also be aware of snapshot is not possible with a rsync daemon setup....
In this view you can let RsyncUI assist in creating ssh-keys and setup global ssh keypath and identityfile, either utilizing default values or set your own. There is some more info about ssh. Local ssh keys found If on RsyncUI has found local ssh keys. Default values for ssh are ~/.ssh/id_rsa and portnumber 22. It is not required to set your own values for key path and identityfile if default values are used....