Whyyyyyyyyy - Can't play music

There are several possibilities for your speakers to lose touch with the YouTube music servers, ranging from simple wifi interference , to duplicate IP addresses in your network, to server problems on YouTube music’s side. One of the nice things about submitting a system diagnostic within 10 minutes of experiencing this problem is that it ‘freezes’ the data so that it can be looked at later. 

So, I’d try a few things. First, read the FAQ that I linked, and think about potential influences to your local network coming from outside, and not inside. I have had issues in the past with things like microwaves, and neighbors with a new router stomping on my signal enough to cause things like you’re experiencing.

I’d also be tempted to refresh my network, merely by unplugging the Sonos devices from power, then rebooting my router, giving it a couple of minutes before plugging back in my Sonos devices. 

And finally, if neither of those solutions work, I’d go down the path of submitting a system diagnostic within 10 minutes of experiencing this problem, and call Sonos Support to discuss it, when you’re able, and they’re open. 

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.