server reporting its agent is unreachable then resolves a few min later repeatadly

[kloczek]

These are passive agent checks that fail, I have no idea why, perhaps you have too many data to be collected and not enough StartAgents for agent. But that is not related to active checks. Look for an entries like cannot send list of active checks .

And looks like in this case it is time to switch to active monitoring.
Passive monitoring does not scale well and/or it works only up to same level of the complexity.

[dimir]

"Not found" means active agent Hostname in configuration file differs from what is in "Configuration -> Hosts". "Not monitored" means the agent host is disabled in "Configuration -> Hosts".

[StephenG]

I know that. It's Okey in my configuration.
How does this affect the main problem, that all windows agent is unreachable random and repeatadly?

[vlam]

I have similar issue on ver 4.0.5 what makes mine even worse on a lot of them I have the resolve time anywhere from 7min to -6min so yes on some it resolves the issue up to 6min before logging the fault on it.
I have gone through all logs and all configs. Network is stable, All servers are running of same NTP servers and on my Zabbix cluster we are less than 2ms difference in time at most. DB server performance is fine. The only thing on my side is all my servers are monitored through Proxies (They use same NTP servers and there performance is fine) and all my agents are different versions as we have not done to many changes on our agents so they currently vary from ver 2.8 to 3.4

I am desperate at this stage as I do not know where to look anymore