Steps to reproduce:

Our Windows support team installed the zabbix agent using the msi, i do not know what options were used during the MSI, but a post configuration was done and the below was set

1. Zabbix agent2 installed as 5.4.3 configured with below options
   1. Server=${ZABBIX_SERVER}
   2. ServerActive=${ZABBIX_SERVER}
   3. Hostname=$(hostname -s)
2. Still no luck so added
   1. TLSConnect=unencrypted
   2. TLSConnect=unencrypted

Now i had the team uninstall the zabbix agent and reboot the server, once done i performed the install and didnt select PSK, it is possible that was selected previously but i cannot get confirmation on that.

Active monitoring is working 100%, but passive is not, the 10050 port is open as per the nmap from the server/proxy. So i am confused as to why. This is happening on 2 of the machines out of 10 that i am testing against.

Host is up (0.14s latency).

PORT      STATE SERVICE
10050/tcp open  zabbix-agent

Issue:

zabbix_get command from server/proxy

zabbix_get [97653]: Get value error: ZBX_TCP_READ() failed: [104] Connection reset by peer
zabbix_get [97653]: Check access restrictions in Zabbix agent configuration

Zabbix Agent logs

failed to accept an incoming connection: from xx.xx.xx.xx: reading first byte from connection failed: [0x00002746] An existing connection was forcibly closed by the remote host.

Expected:
Response