Let me see if I can help you out!

First Check these previous thread's!

* https://en.community.sonos.com/google-assistant-and-sonos-229109/sonos-move-can-t-connect-to-google-assistant-6853347#comments

* https://en.community.sonos.com/google-assistant-and-sonos-229109/sonos-move-can-t-connect-to-google-assistant-device-not-found-6880804

Did they help you out?

* If YES 

Awesome, enjoy you voice assisted speaker!

* If NO and you have previously had your device connected before to the Google Assistant lets try this next step!

First go to your google home app>click the gear icon (after the page should read "home settings" )>Works with google> Reconnect account and follows steps

(You may see a device connect and add to your sonos device count )

If Reconnect account doesn't work try Unlink account and follow steps

* Now go back to the Sonos app and try to connect the Google Assistant again and you should be good to go!