I have updated to the new app release, but it was doing the same thing before the new release too.

I have same issue with music cutting in and out, mainly out. It thinks it’s connected but no sound. I’ve reset the products and router and still the same issue since the update. I now can’t group and play music on my living room from an era to 2 play 1’s and a playbar. 

Seems like the speakers are having trouble keeping in touch with each other, and your router, which doesn’t have much to do with your internet speed, just your local LAN speed. 

I’d try powering down all Sonos devices, and then reboot the router. Give the router a couple of minutes to reboot before plugging back in the Sonos devices. This will force the router to reload its OS, as well as the Sonos devices, and the Sonos devices will ask for new IP addresses from the router. 

Thank you. I will give that a try.