Not enough information here to really make a substantial guess. I’m using S2, and am listening to a stereo paired set of PLAY:3s as I write this, so they do function.

Which Sonos OS are you using? What device is your controller on, and what OS is that device running? Please don’t reset your speakers again, that erases data that Sonos might have used to help you, and rarely ‘fixes’ anything. What are the status lights showing? Where is the ‘add a device’ process failing, and what is the precise error message you’re receiving? Have you tried temporarily connecting them to your router with an Ethernet cable so they can be set up, then the cable removed? Have you tried 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.

Thank you for your reply. I have now managed to get them working and indeed used an Ethernet cable temporarily to get them linked to the soundbar and WiFi