Have you rebooted both your speaker and router? What service are you using to reach this station?
I would recommend that you submit a system diagnostic within 10 minutes of experiencing this problem, and call Sonos Support to discuss it.
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 phone folks, they have tools at their disposal that will allow them to give you advice specific to your network and Sonos system.
Thanks @torsion13 for documenting the issue.
Frustrating this still hasn’t been fixed, I remember speaking to CS nearly a year ago about the encoding issues.
For me it’s all purchased music, if I get something from Apple Music via the subscription it always plays fine, if I bought a track from the iTunes store it’s unplayable, and this is consistent.
A track only becomes playable if it transitions from a purchase only to being available via the subscription, in which case it’ll start to work.
Not sure exactly how to fix this as it’s clearly not just a Sonos issue, as my car can’t play purchased tracks either.
OK, so I am having the same issues as everyone. I have like 100 Grateful Dead concerts in my itunes match library that do not play on my ERA100’s. This is INSANE.
In order to do that stupid work around involving starting playback on a non-Airplay speaker then grouping in my ERA100’s, what older gen speaker can I get to do this?
Thanks so much! I’m such a novice to this and my heart sunk when I could not access my Itunes Match library.
You need either a Play1 or Play 3 if you can indeed pick one up second hand. I’ve noticed they seem to be getting rarer and pricier too!! Can’t think why Sonos?!
Thanks so much for your response Gbiker. It’s really wild I may have to do this. I was so excited to develop this entire new sound system, only to be kicked below the belt.
I found a refurbished Play 1 for $180.
Do you have experience doing what I’m looking to do?
Hope it provides a solution for your music listening Washufisi. Glad to help. Just wish Sonos were! I’ve invested well over £5k on speakers and this situation is so annoying and all they want to do is blame everyone else. To add insult to injury my 30 month old Roam died the other day having got stuck in sleep mode for no reason. Totally shot. Wont be buying any more Sonos stuff that’s for sure!
Sorry forgot to say that the solution works for me. Start playback on the old Play 1 then add in the air play speakers using the S2app. Turn the volume off on the Play1 if you don't need to listen to it.
Oh no! I’m really sorry to hear about your speaker death. That sucks. Hopefully Sonos addresses this issue themselves soon so that we all can continue to enjoy our large investments for years to come. I had no idea at all that this may perhaps be an issue. I sort of feel like an idiot for not researching it enough, but oh well.
Unfortunately, welcome to the club! 

Sonos broke this with their rubbish S2 app update which they clearly have no inclination to or idea how to fix. Since then they blame Apple, Amazon, Spotify, YouTube and just about every other music streaming service, which is palpable nonsense. Bit by bit I am replacing all their speakers and look forward to the day when their products are a distant memory!!
I have the same problem playing via YouTube Music. Please fix this, Sonos!
Where does this music live?
Wow, I’m still having the same issues. SO frustrating! Thanks to those here that gave the Play 1 work around. It really does work. Shouldn’t still have to be doing that though!!
I have Play 3 and I just have my library of MP3s on OneDrive. Only a handful of songs work. Has there been any overall update on this?
Sonos has never been able to play music stored on the OneDrive cloud system.
Sonos has never been able to play music stored on the OneDrive cloud system.
Not remotely true: Microsoft supported this with the Groove service, until they didn’t. There is a third-party integration available somewhere as well.
Interesting. Thanks for the correction.
I found a solution that seems to work. As mentioned before, you can search in the Sonos app for the artist/album/song and play that way instead of going to your Library. Or the fix I discovered consists of the following steps on my Mac.
Go into the Music app and:
1 - Right click on the artist or album and Remove Download
2 - Right click and Download again
3 - Find the artist/album folder in iTunes -> iTunes Media -> Music
4 - Copy the album folder somewhere else temporarily
5 - Back in the Music app, right click the artist/album and Delete from Library
6 - Go to File → Import to Re-import from the previously copied folder
7 - After it has synced with iCloud (will show down arrows for each song, may take several minutes) test in Sonos to see if it plays now
8 - Delete the copied album folder
Hope this helps!