PfSense blocking Zabbix agent

[fk4rp6]

I'm having trouble with the pfSense blocking the Zabbix agent.  Looking at the server it looks like information is getting through some of the time. But most of the time it says that it can't contact the firewall.  When looking at the firewall logs I can see it's blocking it. What should the rule look like so that pfSense will stop blocking it?