How to understand why the server crashed?

Question

Debian

Yesterday the server went down, they turned it on only today. How to understand why there was a fall? What logs and where to look?
/var/log/messages for yesterday only contains this:

May  3 06:25:01 localhost liblogging-stdlog:  [origin software="rsyslogd" swVersion="8.24.0" x-pid="583" x-info="http://www.rsyslog.com"] rsyslogd was HUPed

kern.log starts today, after enabling
kern.log.1 ends on April 19
Nothing in syslog except cron task launch log
Debian 9 system amd64
Where to look?

Answer 1

Nowhere, it means that the server fell like pressing the reset key and did not record anything, it was necessary to look at what the screen shows and raise the netconsole also sometimes helps to diagnose