Hi @DougAM.

Welcome, thank you for reaching out to Sonos Community.

Since it's not working perfectly in the Sonos application, I suggest to remove and add back the youtube music service in the Sonos app.
Let us know if it works. If you need help with any other information, please be sure to let us know.

Thanks. I had tried that. Same result,  just a partial list, like A to J of the artists. 

There are multiple threads on the deficiencies of the current YTM SAMPI service. Its pretty terrible, you need to find an engineer at the ad company called Google and ask them to fix it.

I’m just an old guy new to this stuff.  Google Play Music worked fine with my Sonos but YTM is not.  With Google Play Music going away I hope Sonos comes up with a solution before my Sonos is nothing more than a paper weight.

As noted by controlav, this isn’t a Sonos issue to fix, it has to be fixed by Google. The API provided by Sonos already works, as proven by the fact that the implementation that Google Play Music worked. There’s been no change in that API, it is just that the engineers at YouTube Music haven’t put the same effort and care into their implementation. Unfortunately, Sonos has no access to the YouTube Music codebase, and has no ability to affect change there. 

Don't know what API is but all the songs show up on the YTM app but not on Sonos app.  Are you saying everyone using YTM on the Sonos app has this same issue of not all songs showing up?

https://en.wikipedia.org/wiki/API
 

Yes, that is what we are saying. The YouTube Music folks have not done all of the appropriate work required, which the Google Play folks did. 

Okay.  Thanks for the response.   So it sounds like a just wait and hope Google gets this working properly.  

On one of the other YTM threads the Moderators posted a link so you can report your complaint to YTM directly.

This is the main YTM thread: https://en.community.sonos.com/troubleshooting-228999/youtube-music-not-listing-full-library-6846694

The solution is quit YTM for music storage and switch to iBroadcast.  It works great with Sonos and is *FREE*!!