Maybe try wiring one Sonos device to your main router (temporarily) and perhaps just see if that gets things working again for you… obviously also ensure your Sonos controller device meets the system requirements and is connected (over WiFi) to the same router.

https://support.sonos.com/s/article/4875

Hi Ken,

done all that and still no joy!

Helen

See this link:

https://support.sonos.com/s/article/4908

It seems like your devices cannot get through to the Sonos servers, even when wired, so I suspect it’s a possibly a DNS issue with your router. Perhaps reboot the router first of all ..and if that doesn’t fix it then (if your router allows) try a different DNS server, like the Google public DNS servers 8.8.8.8 or 8.8.4.4 and see if that allows the connection.

Thank you, I’ll see if that works. 

Could also be VPN (work profile of some type?) that blocks access to that server….