Open port 12489 for nrpe

I'm learning a little bit of nagios and unix(buster), and im getting an error related with monitoring CPU LOAD and MEMORY USAGE The feedback I get from the monitor is connect to address 192.168.1.94 and port 12489: Connection refused could not fetch information from server So I went to the client machine and ran netstat -an, and the port doesnt seem to be listening. I tried to add some rules on iptables, did some rules for port 12489 on TCP the port was there on "ACCEPT tcp -- anywhere anywhere tcp dpt:12489" sudo iptables-save what am I missing? the machines are in the same local network am im missing some configuration or plugin? Thank you