I have a remote, headless and unattended machine that runs Ubuntu 20.04 Server.
I also installed gdm3 in order to have a remote desktop to simplify some operations.
To remotely access the desktop I use Zoho Assist but as far as I understand the problem I'm experience is for any VNC connection.
It happens that when I run the PC with monitor attached I can see the desktop. Instead, in the operative conditions (without the screen) I can make the connection but the screen appears black.
So I'm trying to follow this approach:
xrandr --fb 1280x1024
From the Zoho Assist command prompt (that is more similar to a keyboard connected to the machine rather than an SSH connection) I get this:
$ echo $DISPLAY
$ :0
$ xrandr --fb 1280x1024 --display :0
$
But nothing happens. I still see the black screen if I try to connect.
Please not I configured gdm3 to boot with X11 - not Wayland.
