[#ZBX-23491] Zabbix Agent cannot connect to Zabbix Server

I am registering connection problems with the Zabbix Server with all my Zabbix Agents (Active). The agent tries to make the connection for the first time and fails, but when it tries a second time it works correctly. Example of a Zabbix Agent2 log:

2023/09/28 13:00:27.149610 [101] active check configuration update from host [machine_zabbix_agent] started to fail
2023/09/28 13:00:36.147088 [101] cannot connect to [zabbix.server.com:10051]: dial tcp :0->172.20.0.2:10051: i/o timeout
2023/09/28 13:00:36.147129 [101] active check configuration update from host [machine_zabbix_agent] started to fail
2023/09/28 13:00:37.263865 [101] history upload to [zabbix.server.com:10051] [machine_zabbix_agent] is working again
2023/09/28 13:00:42.149955 [101] active check configuration update from [zabbix.server.com:10051] is working again
2023/09/28 13:01:14.149804 [101] sending of heartbeat message to [zabbix.server.com:10051] is working again
2023/09/29 05:31:05.147825 [101] cannot connect to [zabbix.server.com:10051]: dial tcp: lookup zabbix.server.com: i/o timeout
2023/09/29 05:31:05.147892 [101] active check configuration update from host [machine_zabbix_agent] started to fail
2023/09/29 05:31:11.150494 [101] active check configuration update from [zabbix.server.com:10051] is working again

There are approximately 130 hosts that are suffering from these errors, and there are only 3 hosts of those 130 that use Zabbix Agent2, the rest use Zabbix Agentd.

Server=zabbix.server.com
ServerActive=zabbix.server.com

I have tried increasing the Zabbix Server "Timeout" parameter from 3 seconds (default) to 12 seconds, but it didn't work:

I have also tried changing the Kernel configuration of the machine where the Zabbix Server service is located, and it did not work either:
net.ipv4.tcp_fin_timeout = 60
net.ipv4.tcp_keepalive_time = 3600
net.ipv4.tcp_max_syn_backlog = 2048
net.ipv4.tcp_tw_reuse = 2
Thank you very much for your time!!

[ZBX-23491] Zabbix Agent cannot connect to Zabbix Server Created: 2023 Oct 02 Updated: 2023 Oct 03 Resolved: 2023 Oct 03
Status:	Closed
Project:	ZABBIX BUGS AND ISSUES
Component/s:	Agent (G), Server (S)
Affects Version/s:	6.0.22
Fix Version/s:	None

[ZBX-23491] Zabbix Agent cannot connect to Zabbix Server Created: 2023 Oct 02 Updated: 2023 Oct 03 Resolved: 2023 Oct 03