Check that your WiFi is enabled and connected
Go to the WiFi settings on your computer, phone, or tablet, and confirm it is connected to your home WiFi network. This is NOT within the Sonos app, but the settings of the device you are using.
Make sure you're within range of your router
If you're too far from your router you may not be able to get a WiFi signal.
Confirm that you're connected to the right WiFi network
Even if you're in your home, your phone, tablet or computer might have automatically connected to a network other than your home WiFi. Take a moment to check you're not connected to a guest or public network, like "Xfinitywifi" or "Netgear-Guest."