I wrote this summary since it wasn't 100% clear to me how this works rsync server works.

Rsync is using modules when running as a daemon. A module is a share of sort.
Compared when running rsync over ssh that I usually do it's not an absolute path.

To list modules on a rsync server do run this command

rsync -rdt rsync://IPADDR:RsyncPort/

Running that command towards your QNAP it will list all the shares you have.

I set my new little Raspberry Pi OMV NAS to pull files from my main QNAP using this uri:

user@server::share

User and password for rsync is setup in backup station in QNAP, share is one of the listed shares from the previous command.

I set recursive, times, archive, preserve extended attributes.