This is my very first post here

I would like to manage my Denon CEOL N9 through Domoticz (installed on a Rpi).
For this, I followed this tutorial :
https://www.domoticz.com/wiki/Python_Plugin_Manager
I've then clicked on Setup > Hardware > I entered a name > in type, I selected "Denon/Marrantz"
Then cliked "Add" and "Update"
I then stopped / started the Domoticz service.
But the issue I encounter is that when I check into Setup > Devices, there is no new device added...

I've tried with any other plugin, which each time leads to the same result : nothing in the "Devices" menu.
I should have made something wrong but cannot figure out what...
Could you please help me to solve this issue?
Thanks a lot in advance!

Julien