Best answer by Airgetlam
Unplug all of your Sonos speakers from power.
Reboot your router, and give it a minute or two to fully boot up.
Plug back in your Sonos devices.
If this does indeed fix the issue, I would encourage you to look in to reserving IP addresses for all devices on your network. If a router gets into this state once, it’s certainly plausible that it will again.