Authentication is working and the locally hosted web application both successfully initializes new Spotify.Player(...) and starts to play the audio.
Requests to /v1/me/player/play return a 204, however, playback is not modified to desired Spotify URI:
uris: [<track uri>]
Also the API returns a 404 ( "Player command failed: No active device found"), if no other Spotify Clients are open. The request contains query parameter device_id of previously created new Playback SDK player instance, which is activated with PUT request (204) to /player endpoint with the following body:
Am I missing something in the documentation? Does localhost have affect on the Playback SDK's behaviour?
Thanks in advance.