I have been having ongoing issues with streaming SirusXM for years now. This is one of my main uses of my Sonos. Now the stream plays for 15 min at a time and the cuts out with an error stating “Unable to play ‘channel here’ - the song is not encoded correctly.”
Best answer by Ken_GriffithsView original
If you were to search the community here, you will see the error message mentioned is not restricted to the SirusXM service, but is often a network connection issue, as can perhaps be seen from this link (just as one example of many):
My own thoughts and suggestions are, if you are running your speaker(s) on a WiFi connection, perhaps try the router on a different non-overlapping WiFi channel on the 2.4Ghz band, so use either channel 1, 6 or 11 and if your router allows, set a channel-width on 20Mhz only to help reduce interference and see if those things resolve the issue.
If running your Sonos devices on SonosNet, then in addition to the above set its channel so that is 5 or more channels away from the chosen router channel and if you do not have any portable Sonos products (Move or Roam) setup in the System, then also remove the local WiFi credentials from the Sonos App as outlined in this LINK.
Hope that resolves your issue.