I have installed Nagios XI on a clean install CentOS 9 VM but I am having some troubles adding hosts and was hoping someone might be able to help.
I have tried adding both network switches via SNMP and some servers via the basic ICMP option as a test. Every time I get a sad face error with the server IP - "didn't send any data" (image attached)
Now I will admit, I am a noob with both Nagios XI and Linux but the install is so basic I can't see what I could have done wrong.
I do have all of my switches currently being monitored via LibreNMS without and I used the same SNMP details
Any assistance would be much appreciated

Thanks