Deduct host availability from active agent

[X4V1]

Hello,

I setup Zabbix server and installed Zabbix agent 2 on some hosts then configured host in the UI.
On hosts, I just configured:
- Server=<Zabbix Server IP>
- ServerActive=<Zabbix Server IP>
- Hostname=<A name for the host to monitor>
Everything else was left untouched.

Host config looks like this:


If I check in Monitoring > Hosts and hover the availability icon (ZBX):

Here I don't understand why the status of "192.168.0.124:10050" stays "Unknwon".

Is it normal when using the active agent ?

I'm trying to understand that because I can see that all hosts does not have a availability status:

So I checked the documentation and I found this:

and

So I have 2 questions:

1. Why the status of "192.168.0.124:10050" (in Monitor>Hosts) stays "unknown"
2. How can I fix the host availability visible in the dashboard (widget) ? In the documentation is says

   Active checks are considered unavailable when the active check heartbeat is older than 2 x HeartbeatFrequency seconds.

   . How can I deduct the availability on the dashboard in a similar way? In my head it's kind of simple: active agent is sending data => available. If not data received for 2 heartbeat => not available.

[cyber]

Status unknown is there as you probably have no "passive" items added to that host.
Cannot say anything about that widget...