Silvercrest Radio volume_level does not work

I have a Silvercrest radio where I want to set the volume via a script. But this doesn’t seem to work. Does anyone have experience with this?

- alias: "Office Light on"
  trigger:
    platform: state
    entity_id: light.buero
    from: 'off'
    to: 'on'
  action:
    - service: media_player.volume_set
      data:
        entity_id: media_player.sird_14_c2
        volume_level: 0.5