Can you give us more details about your setup? How many Sonos speakers are you using? Which speakers do you own? How large is your home? What is your WiFi setup?

In general, without specifics  such as GuitarSuperstar is asking for, there is the potential of wifi interference, or a duplicate IP address issue blocking communication with the speakers.

It may be worth at least trying a network refresh, there is no cost but time. Unplug all Sonos devices from power. While they are unplugged, reboot the router. When the router recovers, plug back in the Sonos devices, wait a couple of minutes, and test.