Zabbix agent on hosts is unreachable for 5 minutes.
HOW FIX IT?

The situation is as follows: zabbix server version 3.0.4 zabbix agent version 3.0.4
Download from suiviperf.com agent.msi and using Orca to modified and extended to the hosts.
In zabbix configured: Configuration - Actions - Event source -Auto registration- Create action.
It's all ok.
Name like "some host"
Operations: Add to host groups: Servers
Link to templates: Template OS Windows
Status Active.
And so, zabbix already haved 7 servers with zabbix agent (active) (installed by same msi package).
Everything worked is perfectly.
But after adding new 40 hosts (with active agents) zabbix an error for all hosts
with active agents, including zabbix server – "Zabbix agent on hosts is unreachable for 5 minutes".
And also this agent is green via web-interface.
zabbix_get -s 127.0.0.1 -k agent.ping
returns 1.
zabbix_get -s "over hosts" -k agent.ping
also returns 1.
set DebugLevel = 4 and check agent logs ---- all right.
.....__ Zbx_zbx_setproctitle () title: 'listener # 2 [waiting for connection]'
50907: 20,161,020: 141036.807 __zbx_zbx_setproctitle () title: 'collector [processing data]'
50907: 20,161,020: 141036.807 In update_cpustats ()
50907: 20,161,020: 141036.807 End of update_cpustats ()
50907: 20,161,020: 141036.807 __zbx_zbx_setproctitle () title: 'collector [idle 1 sec]'
50911: 20,161,020: 141036.807 In send_buffer () host: '127.0.0.1' port: 10051 entries: 0/100
50911: 20,161,020: 141036.807 End of send_buffer (): SUCCEED
50911: 20,161,020: 141036.807 __zbx_zbx_setproctitle () title: 'active checks # 1 [idle 1 sec]'
50909: 20,161,020: 141037.316 __zbx_zbx_setproctitle () title: 'listener # 2 [processing request]'
50909: 20,161,020: 141037.316 Requested [system.cpu.util [, softirq]]
50909: 20,161,020: 141037.316 Sending back [0.489121]
50909: 20,161,020: 141037.316 __zbx_zbx_setproctitle () title: 'listener # 2 [waiting for connection]'
50909: 20,161,020: 141037.413 __zbx_zbx_setproctitle () title: 'listener # 2 [processing request]'
50909: 20,161,020: 141037.413 Requested [vfs.fs.size [/ home, free]]
50909: 20,161,020: 141037.413 Sending back [16061775872]
50909: 20,161,020: 141037.413 __zbx_zbx_setproctitle () title: 'listener # 2 [waiting for connection]'
50907: 20,161,020: 141037.807 __zbx_zbx_setproctitle () title: 'collector [processing data]'
50907: 20,161,020: 141037.807 In update_cpustats ()
50907: 20,161,020: 141037.808 End of update_cpustats ()
50907: 20,161,020: 141037.808 __zbx_zbx_setproctitle () title: 'collector [idle 1 sec]'
50911: 20,161,020: 141037.808 In send_buffer () host: '127.0.0.1' port: 10051 entries: 0/100
50911: 20,161,020: 141037.808 End of send_buffer (): SUCCEED
....................
etc
In sum:
After the addition of about 40 new hosts zabbix agent (active) error occurred Zabbix agent on hosts is unreachable for 5 minutes.
I used default templates and triggers. No errors on zabbix_server.log (Regarding my question) no errors on zabbix_agentd.log. agent is green on web-interface.
zabbix_get -s 127.0.0.1 -k agent.ping (Template App Zabbix Agent: Agent ping) returns 1.
P.S. Sorry for my English. And this is my first post, if I made a mistake...sorry.