What router? Does your router think one or all of your Sonos devices are actually connected to it? Did the installation of the app for your smart meter accidentally disable “local network” access for the Sonos app?

I’m not familiar with your “Smart Meter”. I assume that this is an accessory installed by your power company. As such, this should not impact your SONOS system, but during installation any devices operating exclusively on house power would have rebooted. Rebooting only a few things can introduce conflicts.

Do not Factory Reset without further consult.

I suggest that you shut down everything on your network and restart in the following order:

Modem, if present as a separate ‘box’.
Router, if present as a separate ‘box”.
Network switches, if any.
Wifi access points or mesh points, if present as a separate ‘boxes’.
Wired SONOS UNITS.
Wireless SONOS UNITS.
Network hard drives, if any.
Everything else.

Allow each step to complete before moving forward.

Likely, everything will work now, but you are not done. You want to go into your router and “reserve” or “fix” “IP address” assignments. This can be a little scary and tedious the first time, but this does not need to be redone until you change routers or add a significant number of new devices. Address reservation will prevent this sort of mayhem when there is a power interruption.

Some smart meters use radio signals to pass the information they meter to the power company. In my house the gas meter passes on its infomation by bluetooth to the electricity meter that passes the information via 2G to the power company. Could wifi being disrupted by this for TS? My wifi is fine.

Thank you all for your responses. I will work through your advice and update. Thank you again.