I have recently switched my streaming music services to Amazon Prime and I pay an additional yearly subscription of £21.99 and have uploaded some 22000 plus tracks to their cloud servers. The subscription extends the tracks beyond the usual 250 default track limit.
Most, if not all, of my uploaded tracks are encoded in AAC format mainly 256 of 320 Kbps. I can see the tracks through Amazon (plugin) service in the Sonos app and can play them all directly from within the app. Just to clarify, there are no DRM issues associated with any of the uploaded tracks.
Using Alexa (I believe) these uploaded tracks are accessible from the cloud server using voice commands and it appears the tracks are fetched and added to the requested room (hidden Amazon Session queue) for playing, but for some reason I am getting an encoding error message at the start of playback... see attached screenshot and diagnostic number 8189279.
I know the track concerned in this case will play fine when I use the Sonos app, but for some reason it will not work when fetching it using an Alexa voice command from the Amazon cloud server.