Log trigger

Log Trigger never gets triggered. What am I missing?

- id: '1639257139322'
  alias: LOGS Counter
  description: ''
  trigger:
  - platform: event
    event_type: system_log_event
    event_data:
      level: WARNING
    context: {}
  condition: []
  action:
  - service: counter.increment
    target:
      entity_id: counter.logs_counter
    data: {}
  mode: single