Event trigger for automation: ValueError: day is out of range for month

Configuration
1

Hi all,

Based on a calendar’s event I’d like to trigger an automation:

alias: New automation 
description: "" 
triggers:   
    - event: start     
      offset: "7:00:00"     
      entity_id: calendar.travel     
      trigger: calendar 
conditions: [] 
actions:   
    - metadata: {}     
      data:       
        title: heating       
        message: Heating is being turned off!              
      action: notify.mobile_app_smartphone
mode: queued

Every time this automation is being triggered I receive this error message in my logs:


Error fetching New automation data: ValueError: day is out of range for month

The event usually starts at midnight and seven hours after the event has started the automation should be triggered. Any idea what I could improve? Many thanks in advance!