Local Calendar Notification template error help needed

For the life of me I can’t seem to get this simple automation to work. I have a local calendar with various appointments etc. I want the notification to ping me a pushover notification whenever it encounters a calendar event. Note some events happen at the same time i.e. all day.

EDIT - This only provides a single calendar notification. When I have multiple events during the day.

template automation YAML is as follows.

alias: Calendar event notification
description: ""
trigger:
  - platform: calendar
    event: start
    offset: "-0:0:0"
    entity_id: calendar.local_calendar
action:
  - service: notify.pushover
    data:
      message: This is a {{ states.calendar.local_calendar.attributes.message }}
mode: single

Please show the entire automation. We cannot see what trigger represents — if it’s not a calendar trigger then you’d expect that error.

If you’re testing it by manually executing the automation, that won’t work either: