Indications of either wifi interference , or possibly duplicate IP addresses being handed out by your router. Both my PLAY:3s are working without issue on my S2 system. Speed really doesn’t matter in these two cases, interruptions do. 

Beyond the information in the linked FAQ, I’d also do a simple network refresh, by unplugging all Sonos devices from power, then rebooting the router. Give the router a couple of minutes to come back up, then plug back in your Sonos devices, wait another two minutes, then test. 
 

However, if you do want to contact them, you can call Sonos Support directly to discuss it.

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.

That is a valid link to their page, not a spam link.