Have you tried rebooting your router, followed by a reboot of your Sonos speakers?

Have the same issue across iOS and Android. Have opened a ticket with them, but there's seemingly no awareness about what's going on. They recommend browse as a workaround which obviously is just a different use case. 

The last year I used too much YT Music but since one year ago with an app update the search bar for YouTube music doesn't work anymore, I contacted support and they don’t gave me a solution. But I throught that they had solved it yet. 

The question remains unanswered by many - have you rebooted your router followed by a reboot of the speakers?

Plus is the app updated from the App Store/Play Store, AND is the system updated (Settings - General Settings - System Updates - Check for Updates).

Yes, they do this on the phone with you too. It changes nothing. 

Which is fine for those that have contacted Sonos support but for those that haven’t, you never know when this course of action might create a local fix.

Obviously if it’s a universal issue then that’s a different matter - but I’ve not seen much talk of it on here (yet!).

Yes, I have rebooted my router and speaker, and the apps and system are on the latest updates, the problem still remains.

Again I am able to play songs from Youtube Music, the only thing broken is the search functionality, which is kind of a big deal if I want to play music that is not in my library or part of my mixes.

Interesting, thanks for the confirmation. 

In general, Sonos sends your search request to YouTube’s servers, and shows you what the response is.  What I don’t know is if they aren’t sending the request, the request is not getting there, or they’re not showing the response.

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.

I have sent diagnostics and screenshared with them. No progress. 

Speed of a ‘fix’ would be a variable. It may be that Sonos has to fix things on their side, in which I’d think is more than one update away, as I expect the next update is already locked and loaded, so the one after that at the earliest. But if the needs to be made by YouTube, which seems more likely, given that their haven’t been complaints about searching for all Sonos streamers, then Sonos would have to wait for the engineers at YouTube, since Sonos wouldn’t have access to the YouTube servers and codebase. 

I think I got somewhere with Google - looking forward to seeing a fix.

Google has pushed a fix for this and the issue is resolved on my devices.

Confirmed it is working for me now as well. Thanks ​@Tjw2011