Why is SSH crashing in Ubuntu?

Question

SSH

There is a regular VPS with the usual built-in SSH, there is also apache2 and PHP7.4.
I used it quietly for a while, and today I came across the fact that it doesn’t matter after autoloading or after manually starting SSH, it began to stupidly crash, and in the syslog I found only this:

Oct 14 00:01:18 Ubuntu systemd[1]: Starting OpenBSD Secure Shell server...
Oct 14 00:01:18 Ubuntu systemd[1]: Started OpenBSD Secure Shell server.
<проходит некоторое время простоя>
Oct 14 00:06:02 Ubuntu systemd[1]: ssh.service: Main process exited, code=killed, status=9/KILL
Oct 14 00:06:02 Ubuntu systemd[1]: ssh.service: Failed with result 'signal'.
Oct 14 00:06:05 Ubuntu systemd[1]: ssh.service: Scheduled restart job, restart counter is at 1.
Oct 14 00:06:05 Ubuntu systemd[1]: Stopped OpenBSD Secure Shell server.
Oct 14 00:06:05 Ubuntu systemd[1]: Starting OpenBSD Secure Shell server...
Oct 14 00:06:05 Ubuntu systemd[1]: ssh.service: Control process exited, code=killed, status=15/TERM
Oct 14 00:06:05 Ubuntu systemd[1]: ssh.service: Failed with result 'signal'.
Oct 14 00:06:05 Ubuntu systemd[1]: Stopped OpenBSD Secure Shell server.

Googling did not help at all.
Please tell me, what is it and what is the reason and how is it treated?

Answer 1

PS: The only thing I could accidentally catch in systemctl was status
ExecStartPre=/usr/sbin/sshd -t (code=exited, status=0/SUCCESS)
Process: 2711 ExecStart=/usr/sbin/sshd -D $SSHD_OPTS (code=killed , signal=KILL)
Main PID: 2711 (code=killed, signal=KILL)

Answer 2

Is it a virus that is killing him?
Set up auditd