I need help with port 873

Hello community, I need your help. I have a WD MyCloud EX4100 32TB. And I am enabling the port forwarding that comes by default on the computer.

Also I have a QNAP of 120 TB, what I want to do is the following:

The WD Mycloud, I want to use it as a QNAP backup, and I am trying to synchronize the copies but it asks me to open port 873. I have followed all the steps but apparently that port is closed. Even and entered by console to the WD Mycloud and I do not see said port open.

Can you open that port and work with the backups?

Can you help me.

root@Apolo ~ # vi /etc/rsyncd.conf
root@Apolo ~ # netstat -lt
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address Foreign Address State
tcp 0 0 0.0.0.0:47161 0.0.0.0:* LISTEN
tcp 0 0 localhost:2812 0.0.0.0:* LISTEN
tcp 0 0 localhost:4700 0.0.0.0:* LISTEN
tcp 0 0 0.0.0.0:445 0.0.0.0:* LISTEN
tcp 0 0 0.0.0.0:32799 0.0.0.0:* LISTEN
tcp 0 0 Apolo:49152 0.0.0.0:* LISTEN
tcp 0 0 localhost:8000 0.0.0.0:* LISTEN
tcp 0 0 0.0.0.0:nfs 0.0.0.0:* LISTEN
tcp 0 0 0.0.0.0:45609 0.0.0.0:* LISTEN
tcp 0 0 localhost:3306 0.0.0.0:* LISTEN
tcp 0 0 0.0.0.0:139 0.0.0.0:* LISTEN
tcp 0 0 Apolo:5357 0.0.0.0:* LISTEN
tcp 0 0 0.0.0.0:sunrpc 0.0.0.0:* LISTEN
tcp 0 0 0.0.0.0:48117 0.0.0.0:* LISTEN
tcp 0 0 0.0.0.0:ftp 0.0.0.0:* LISTEN
tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN
tcp 0 0 0.0.0.0:46199 0.0.0.0:* LISTEN

Thank you