Also see this in engine:

Aug 6, 2020, 7:37:17 AM
VDSM someserver command Get Host Capabilities failed: Message timeout which can be caused by communication issues

On Thu, 6 Aug 2020 at 07:09, Strahil Nikolov <hunter86_bg@yahoo.com> wrote:
Can you fheck for errors on the affected host. Most probably you need the vdsm logs.

Best Regards,
Strahil Nikolov

На 6 август 2020 г. 7:40:23 GMT+03:00, Nardus Geldenhuys <nardusg@gmail.com> написа:
>Hi Strahil
>
>Hope you are well. I get the following error when I tried to confirm
>reboot:
>
>Error while executing action: Cannot confirm 'Host has been rebooted'
>Host.
>Valid Host statuses are "Non operational", "Maintenance" or
>"Connecting".
>
>And I can't put it in maintenance, only option is "restart" or "stop".
>
>Regards
>
>Nar
>
>On Thu, 6 Aug 2020 at 06:16, Strahil Nikolov <hunter86_bg@yahoo.com>
>wrote:
>
>> After rebooting the node, have you "marked" it that it was rebooted ?
>>
>> Best Regards,
>> Strahil Nikolov
>>
>> На 5 август 2020 г. 21:29:04 GMT+03:00, Nardus Geldenhuys <
>> nardusg@gmail.com> написа:
>> >Hi oVirt land
>> >
>> >Hope you are well. Got a bit of an issue, actually a big issue. We
>had
>> >some
>> >sort of dip of some sort. All the VM's is still running, but some of
>> >the
>> >hosts is show "Unassigned" or "NonResponsive". So all the hosts was
>> >showing
>> >UP and was fine before our dip. So I did increase
>vdsHeartbeatInSecond
>> >to
>> >240, no luck.
>> >
>> >I still get a timeout on the engine lock even thou I can connect to
>> >that
>> >host from the engine using nc to test to port 54321. I also did
>restart
>> >vdsmd and also rebooted the host with no luck.
>> >
>> > nc -v someserver 54321
>> >Ncat: Version 7.50 ( https://nmap.org/ncat )
>> >Ncat: Connected to 172.40.2.172:54321.
>> >
>> >2020-08-05 20:20:34,256+02 ERROR
>>
>>[org.ovirt.engine.core.dal.dbbroker.auditloghandling.AuditLogDirector]
>> >(EE-ManagedThreadFactory-engineScheduled-Thread-70) [] EVENT_ID:
>> >VDS_BROKER_COMMAND_FAILURE(10,802), VDSM someserver command Get Host
>> >Capabilities failed: Message timeout which can be caused by
>> >communication
>> >issues
>> >
>> >Any troubleshoot ideas will be gladly appreciated.
>> >
>> >Regards
>> >
>> >Nar
>>