Cannot connect to "x.x.x.x:161": Timeout.

[Atul]

We have enabled snmp v3 on all the ESXI host for hardware monitoring but out of 150 ESXI host 3 host does not show the all hardware details and gives us this error on zabbix SNMP status on (ESXI host name) is unreachable for 5 mins.
I have checked all the setting and everything seems fine.
can anyone here suggest something what should i do more?

[Atsushi]

I don't know what environment you are using and how you are trying to monitor it.
ex.
- What version of Zabbix are you using?
- What item are you using to monitor?
- Which template are you trying to use?
- What version of ESXi are you using?

Zabbix's standard VMware ESXi monitoring method is to use the VMware API. Not SNMP. You need to prepare your environment for the template or monitoring item you are trying to use.