Stream from IPhone with app iPCamera

Hello there,
I am fairly new to HomeAssistant and I am trying to use my old IPhone as an IP camera with the app ‘iPCamera’.
Following the great description from @mikeg1130 on

I am now able to pull an image from the IPhone each time a motion sensor picks up motion and I show this image on my chromecast enabled TV.
However, I would like to show a live stream instead of the still image.
I wrote a script as follows, but I get an error message, that the camera does not support
play_stream: “camera.iphone6 does not support play_stream service”. I am a bit puzzled, because the Lovelace UI does show me a live stream, after I click on the still-image preview. So it should somehow be possible to get a stream.
Any help is greatly appreciated!

scripts.yaml:

'1579461249737':
  alias: Chromecast_playCamera
  sequence:
  - data:
      entity_id: camera.iphone6
      media_player: media_player.chromecast_livingroom
    entity_id: camera.testcam
    service: camera.play_stream

configuration.yaml:

stream:
ffmpeg:
  ffmpeg_bin: /usr/bin/ffmpeg
camera:
  - platform: mjpeg
    name: iphone6
    mjpeg_url: http://192.168.0.13/live