I would recommend your next step to be to 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 Sonos system and network.

There are few moderators in this forum who have access to this diagnostic data, and for better or worse, Sonos Support doesn’t work in these forums. 

Resetting my Beam solved the issue of Play 3s and Sub not connecting.