How to see what caused Ubuntu server shutdown?

Question

ubuntu

Hello.
I keep the server on which asterisk is spinning.
Today I discovered that for unknown reasons, it turned off without permission.
It doesn’t look like an emergency shutdown, because. in the logs, the demons reported about the shutdown.
There was also a suspicion that shutdown did unattended-upgrades instead of reboot, but there is no data for today in /var/log/apt/history.log.
Now I'm trying to understand what software caused the shutdown of the server. I did not find this information in /var/log/.
last -x only shows this:

shutdown system down 2.6.32-042stab10 Mon Nov 9 11:16 - 16:30 (05:14)
runlevel (to lvl 0) 2.6.32-042stab10 Mon Nov 9 11:15 - 11:16 (00:00)

Can you please tell me where else I can look?
Added:
It turned out that the server was disabled due to the fault of the VPS provider.

Answer 1

tail /var/log/syslog
history