‘Not encoded properly’ is often code for Sonos saying ‘I can’t recognize this’ or even ‘I can’t read this’. Frequently, IMHO, it shows up when Sonos can’t reach the source. Hard to tell from that precisely what the issue is, unfortunately, so I’d try two things. 

First, a simple network refresh. Unplug all your Sonos devices from power, then reboot your router. Wait two minutes, then plug back in the Sonos. Wait another two minutes, then test. 

But, if this doesn’t change things, since you’ve already done the other troubleshooting step, I would recommend that you submit a system diagnostic within 10 minutes of experiencing this problem, and call Sonos Support to discuss it. Don’t post the resulting diagnostic number here, they get sensitive about GDPR.

There may be information included in the diagnostic that will help Sonos pinpoint the issue and help you find a solution.

When you speak directly to the Support staff, they have tools at their disposal that will allow them to give you advice specific to your network and Sonos system.

Also seeing same. Apple Music 1 playing OK. Chill & Club stations appear to start playing, but then errors ‘not encoded correctly’.

You can AirPlay if you have at least one AirPlay compatible speaker, then group the non-AirPlay compatible in Sonos App.

This sometimes happens when Sonos hasn't updated its app to support the new Apple Music live radio streams. The best option is to wait for a Sonos software update.