Homeassistant event start not triggered

I don’t understand why the event start of homeassistant platform isn’t triggered when I restart the server.

This is my code:

- id: 'ha_start'
  alias: HA start
  trigger:
    platform: homeassistant
    event: start
  action:
    - service: mqtt.publish
      data: 
        payload: "START"
        topic: "HOME/HASS"     

I’m pretty sure that the code is correct but no event is fired! why?

I have a similar automation and its working well.

Try manually triggering the automation and see if it publishes to your MQTT server. Your trigger section looks correct, not sure about the action section. Doing the manual trigger will tell you if its correct.

Is your automation on in Dev Tools/states?

Yes, my automation is on and the MQTT message is sent if I trigger manually the automation.
I’m running HassOS 1.13 on virtualbox (if this can be helpful).