How to trigger automation on unavailable entity?

Configuration
1

I have this automation to notify me if Zigbee goes down:

alias: Notify if zigbee is diconnected
description: ""
triggers:
  - trigger: state
    entity_id:
      - binary_sensor.zigbee2mqtt_bridge_connection_state
    to:
      - unavailable
    for:
      hours: 0
      minutes: 2
      seconds: 0
conditions: []
actions:
 xxx
mode: single

But it does not seem to trigger if the bridge becomes unavailable. I think it is because the entire entity becomes unavailable somehow?

Screenshot_20260124_124243
Screenshot_20260124_124243710×515 28.6 KB

How can I make it trigger when the entity becomes unavailable?

2 
    to:
      - unavailable
      - unknown