Ubuntu 20.04.3 desktop (Cinnamon) - SSH disconnects when user logs off the desktop!

[Bo Berglund]

My new install of Ubuntu Desktop 20.04 LTS on an HP PRODESK 400 G4 Desktop Mini
is misbehaving on SSH!

I will normally interact with it only using SSH but for some strange reason the
SSH server seems to disconnect the SSH client session when the user logs off the
desktop!
Why is that so? And can it be changed?

The disconnect does not happen directly when I log off from the desktop but
after some time (a couple of minutes) the SSH session (via PuTTY) just
disconnects mid way in a file edit or other activity! At the same time I hear
from the box how the data drive is powered off and the heads parked.

After this it is not possible to connect by SSH anymore, I have to physically
log on to the desktop on the monitor first!

Where can this be configured away? Why is an SSH session tied to the login state
of a user to the desktop?

My use for this system is mainly as a server but I installed the desktop so I
could use it via VNC later on. VNC is not yet installed though.
The desktop I use is Cinnamon, which I installed after the main install was
done.

Note that my two HP laptops and the Lenovo server I also have running Ubuntu
20.04.3 do not do this, my connections stay up for days on end.
So I was not prepared for this strange behaviour.


-- 
Bo Berglund
Developer in Sweden