Hi!
We are using Spotify Web SDK in our system, with the intention of playing the music within our web application. The player itself is opened in a different browser tab, and we need to control it through the API.

We create a playback device in the browser tab, then use its ID to control it. In the web playback, there’s an event ‘ready’, and through the event handler we get the new media device ID.

Then, when we want to activate the player, we are using ‘Transfer Playback’ call with the received device ID. However in many cases the call returns 404 (device not found) or 502 (bad gateway) errors instead of starting the playback. The success seems completely unpredictable – sometimes it works OK, and sometimes it does not. Repeating the call multiple times may help, but in many cases the errors persist, even though the player exists and is ready.

Running ‘Get Available Devices’ returns the device in question, is_active is true, is_private_session is false and is_restricted is false.

Any advise would be greatly appreciated:)