Ubuntu: Cant connect to printer

What is the problem?

I have connected my Ender 3V2 directly to my Synology 920+ NAS via USB cable.
Synology sees the device; I assign the USB port to my Ubuntu Virtual MAchine, hosted in the Synology

I fire up the Ubuntu VM
I installed both Ponterface and Octoprint from the apps library (Ubuntu software

I start Ponterface, and its already set to connect to /dev/ttyUSB0
I click connect and immediately I am connected to the printer
I can move the head clicking the arrows in the UI
I close the app and I start Octoprint via Mozilla by going here
There is no way I Can connect either via AUTO ori manual settings exactly as in Ponterface

I get the message
Unexpected error while connecting to serial port: /dev/ttyUSB0SerialException: '[Errno 13] could not open port /dev/ttyUSB0: [Errno 13] Permission denied: '/dev/ttyS0'' @ comm.py:_openSerial:2691 (hook default)

What did you already try to solve it?

I already made sure I am in the groups tty dialout

Hello @KiloMeater

Did you minimized Pronterface or shut it down?

i tried both but no difference
(I close the Ponterface app by clicking the X on the upper right corner on its window , I hope its enough )

Unfortunately we've seen a number of issues with the app offered through Snap on Ubuntu. It's not an official distribution and it regularly comes around here with permission issues trying to connect.

You can find the official instructions on how to install OctoPrint on Linux below: