Server agentd up show up, but system inform unreachabled

[gavinfang]

Hi guys

My zabbix have a problem, sometimes system show unreachabled, but when i going to look this issue in zabbix (server > agentd ping) but it's but.

And in the dashboard that server show unreachabled (and is recovered after 5~30s) then show unreachabled again.

I don't have any idea about this and how to fixed it

Anyone have this problem like me?