TrueNAS rsync pull problem

Hi,
I am trying to do a rsync pull task from my qnap Nas to pull data to TrueNAS scale.

I generated a public key on qnap and copied it to the home direction in the user folder of my truenas.
I also tried it with SSH credentials, but I am not able to establish the ssh connection.
Use of the ssh keys via windows works just fine.

What am I missing out?