Why does docker exit?

For various reasons, I've installed and uninstalled ("rm") docker installations of Plone.

several of this "exited" as seen by sudo docker ps -a

this takes down the site and a restart is required to start the site.

Why does this happen? I've looked here: https://www.tutorialworks.com/why-containers-stop/

But this talks about docker exiting because it finishes it's process. of course Plone should never finish and thus should not exit.

I tried looking at the logs - extremely long and it didn't help me.

Ideas?

Difficult to guess with the information provided. Can you elaborate a bit more?