ESXi 6.5 host unexpected reboot

Hi all,

On /var/log/hostd.log can't find the keywords as below:

Hostd: [12:51:54.284 27D13B90 info 'TaskManager'] Task Created : haTask-ha-host-vim.HostSystem.reboot-50

or

DCUI: reboot

Another hit can trobleshoot?

We've 3 ESXI host running same version with vCenter and one of them just reboot last night and VM failover to another host.

Thanks.