ZBX_TCP_READ() timed out message error

[igorw]

Hi, I ran into problem with setting up Zabbix service. Seen that kind of an error for the first time. After installing Zabbix agent on Target machine and add it to inventory on Zabbix dashboard, I see follwoing message:

Get value from agent failed: ZBX_TCP_READ() timed out

I have ping connectivity between Zabbix and Target machines. Port 10050 is also opened - I have checked it using nmap. There is no firewall enabled on Target machine. I have many other machines monitored by the same Zabbix and had no issues like this before.
I am not sure how to resolve this issue and will appreciate any help.

From log, IP deleted before posting:

2667:20200714:035732.988 Starting Zabbix Agent [zabbix]. Zabbix 2.4.7 (revision 56694).
2667:20200714:035732.989 using configuration file: /etc/zabbix/zabbix_agentd.conf
2667:20200714:035732.989 agent #0 started [main process]
2668:20200714:035732.990 agent #1 started [collector]
2669:20200714:035732.991 agent #2 started[listener #1]
2670:20200714:035732.991 agent #3 started[listener #2]
2671:20200714:035732.992 agent #4 started[listener #3]
2672:20200714:035732.992 agent #5 started [active checks #1]
2672:20200714:035733.142 active check configuration update from [X.X.X.X:10051] started to fail (ZBX_TCP_READ() failed: [104] Connection reset by peer)

[Hamardaban]

Everything is written in the log for you: the agent can't connect to the server to pick up the configuration of active checks. Either configure the agent only in passive mode, or check the server availability from the agent.

[igorw]

Everything is written in the log for you: the agent can't connect to the server to pick up the configuration of active checks. Either configure the agent only in passive mode, or check the server availability from the agent.

Thanks for answer. I have ping from VM with agent to Zabbix server. Also nmap shows ports 10050 and 10051 opened.
As for the passive mode, I do not fully understand how it works. I need agent to monitor real-time parameters on the machine with agent, like CPU, disk space, ping etc. and send alarms, when some thresholds are crossed. Does it possible in passive mode?
Franky, I do not understand this issue at all, while I have configured many Zabbix sites for my purpose (okay, not being expert in it). I have connectivity between VMs, agent is installed correctly (I believe), but see that message I have never occured before.

[Hamardaban]

https://www.zabbix.com/documentation/current/manual/appendix/items/activepassive#passive_checks