Squeezebox configuration

Hey guys

I hope, i got the right category.
I’m trying to automate my squeezeboxes.
Home Assistant is installed as Core application on my Synology NAS.

I want to use a playlist from Spotify in LMS. LMS picks up the playlist, but the action goes into a loop and never finishes. Is there a way to integrate a timeout for this?

service: media_player.play_media
target:
  entity_id: media_player.squeezebox_schlafzimmer
data:
  media_content_id: "16171"
  media_content_type: playlist
metadata:
  title: "Spotify: Sleep lofi"
  thumbnail: null
  media_class: playlist
  children_media_class: track
  navigateIds:
    - {}
    - media_content_type: Playlists
      media_content_id: Playlists
    - media_content_type: playlist
      media_content_id: "16171"

Second, I want to set the music to 18. But I think the parameters are delieverd wrong. Because I can set the sleep time, but that only has 1 parameter instead of 2 like the command mixer. Has anybody managed to set the volume on a Squeezebox? If so how?

Working sleep command:

service: squeezebox.call_method
data:
  command: sleep
  parameters: 40
target:
  entity_id:
    - media_player.squeezebox_schlafzimmer

Not working mixer command.

service: squeezebox.call_method
data:
  command: mixer
  parameters: volume, 18
target:
  entity_id: media_player.squeezebox_schlafzimmer