Multiple agent down host daily

[pedos]

Hello
I migrated a Zabbix server from the typical installation on Ubuntu, Apache, etc., to Zabbix Docker 7.0 LTS.
Since the change, I’ve been getting 'agent down' alerts for all configured hosts (226 hosts) every day at 11:00 PM approx, and the recovery message comes 2 minutes later.
It’s as if my Zabbix machine freezes at that time.
Does anyone know what might be causing this?
Thanks for your help.

[LenR]

Look for "external" factors. Check the Zabbix log, does housekeeping run at that time? Do you see long queries at that time? Does some backup run at that time? Do you have other up/down tests on those hosts? What does their data show at that time.

[pedos]

Thanks for replying.
For now, I've resolved it by increasing the trigger "Problem: nodata(/HOST/agent.ping,120s)=1" from 60s to 120s.
I don't see anything unusual in the logs of the Zabbix server and MySQL containers.
Housekeeping runs every hour.
I don't know how to check for long queries.
I'm not running a full machine backup at that time either.
When I check the host's historical data at that time, there's no interruption.
I've cloned the machine and left it monitoring only one host, and the issue doesn't occur.
Best regards.