Understanding sending proxy heartbeat to Zabbix

[AlBoPo]

Hello,
I'm new to Zabbix and I'm looking on how to write a Zabbix agent for a specific hardware.

So first I'm trying to Simply send an heartbeat.

I declared my Template and a corresponding Element named `heartbeat` of a type `Zabbix trapper` with a corresponding trigger where I wrote the expression as follow (FX30 is the name of my Template):

{FX30:heartbeat.nodata(20m)}=1

So on the dashboard, I can see that my hosts using this Template are currently showing this problem which seems to be as expected.

So now is the part where I don't really understand everything.

I wrote a program on my remote target which is supposed to send its heartbeat every 10 minutes and I send the following json string:

'{"request":"proxy heartbeat","host":"LL709601401410"}'

Maybe I forgot the version as I just saw in the doc.

And the server responds:
{ "response": "success" } As expected.

Anyway, the hosts are still displaying the problem but I think I don't send what they are waiting for.

In fact in the doc here (https://www.zabbix.com/documentation...ndix/protocols), as I created a Zabbix trapper type of trigger, I wonder if I wouldn't have to use Sender data as explained here (https://www.zabbix.com/documentation.../items/trapper).

So I tried, I verified that I actually send the request as explained:

{ "request":"sender data", "data":[ { "host":"LL709601401410", "key":"heartbeat", "value":"1" } ] }

Zabbix answered {"response":"success","info":"processed: 0; failed: 1; total: 1; seconds spent: 0.000031"} .

Well, ok but what is the reason for the failure??

I looked at the latest data:

https://i.imgur.com/2R7cxpl.png

But in fact I don't understand if it received something and when and which between all my tries caused this and even if it was caused by somthing sent....

Can you explain me what I didn't understand please?

Alain

Using version 3.4.12