Zabbix Server does not find Proxy's hosts

[Xenon032]

Hi, I configured zabbix proxy and zabbix agent on pfSense. I can see status "online" for the proxy from the zabbix server but not the proxy's hosts and I don't understand why... on agent's logs there is this error: no active checks on server [5.6.7.8:10051]: host [pfSense] not found.

My configuration (with invented public's IPs, just to see):

• Zabbix server (a Centos machine with firewalld disabled) is inside my LAN with 192.168.1.220 IP and it goes online with FW's LAN public IP 1.2.3.4 (plus there is a rule that open and redirect the 10050 and 10051 ports to zabbix server IP, so I can reach zabbix server from outside).
• Zabbix proxy is a remote pfSense (5.6.7.8 IP WAN interface, so the public IP) and on pfSense I opened 10050 and 10051 ports on WAN to allow 1.2.3.4 to 5.6.7.8 .
• Zabbix agent on pfSense is configured to point 5.6.7.8 (the proxy).

So, on Zabbix Server I see the proxy "Test" online (so this is OK), BUT the proxy host "pfSense" does not work, zabbix server cannot see it.

PS: I tested 10050 and 10051 ports from server > proxy and proxy > server successfully.

Versions: Zabbix Server (5.2.0) on Centos 8 with mysql 8.0 and PHP 7.4; Zabbix Proxy5 (1.0.4_5 pfSense); Zabbix Agent5 (1.0.4_6 pfSense).