As you have apparently found out, a factory reset is almost never a good idea, unless directed to be done by a Sonos employee.

If connecting one of your previously working speakers to your router with an Ethernet cable doesn’t bring them back online in order to submit a diagnostic, then your best bet would be to call Sonos Support directly to discuss it. Unfortunately, there just isn’t enough information in your post for those of us in the community to begin to guess where the issue lies.

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. I was following a Sonos guide and I only reset the one speaker that appeared to be causing alll my problems! I will call them tomorrow.

That would be your best bet. It could be anything from bad hardware (extraordinarily rare) to an issue with your router which may have updated the firmware without your knowledge. Wiring a single speaker to the router and then submitting a diagnostic before talking to them on the phone would go a long way in helping them diagnose the issue.

thanks again. I have tried wiring a speaker to the router, but even that isn’t recognised!

Then talking to someone at Sonos is likely best. The only reasons I can think of for that kind of failure are: 1) Software failure 2) Hardware failure in the speaker, or either port the cable is plugged in to, or a bad cable.

But not having all the details of your system, it’s hard to diagnose via text.