Can you get music to play if you use the desktop app? 

Agreed with @Bumper . The app is flaky but the Windows, I know you said Mac, app has been my savior.

The web app, while pointless IMO, has been working pretty well for me also.

Try sometime other than the app as a test.

Same problem here.  Playlists stop playing, skip to next song or Tune In will stop all together and start back sporadically.  Have had Sonos for 6 or 7 years and has been great until recently.  

If the speakers are stopping playback, then if that’s part-way through a track in your playlist then just to say, that’s nothing to do with the new Sonos App.

The Sonos App itself, is just a ‘remote’ for your Sonos players. So as an example, you could start your playlists playing and fully close the App and even shut down your mobile device and your speakers should carry on playing.

So if the music is stopping, then no controller App will solve that - you likely have a LAN/WAN network issue between your audio source and your Sonos speaker(s). So I suggest don’t waste your money on 3rd party Apps. You need to first find what’s causing your speakers to stop playing. Maybe start with this Sonos Support link instead…

https://support.sonos.com/en-us/article/reduce-wireless-interference

^its probably the app, it’s buggy AF. I mean there’s thousands of posts in the community with people having issues with the app. Try the desktop app. If it works you’ll have the likely answer. 
 

Definitely no need to spend any money, the desktop app is free. Though SonoPhone is only $3 or so depending on your local currency. If the desktop app works so will SonoPhone since they use the old way of communicating with your speakers. IME money well spent but ymmv.