Hard to tell, with so little information. What happens when you connect the device with an Ethernet cable, temporarily to your router? Have you called Sonos Support directly to discuss it?

You could try a search here for your modem, if that fails try another search engine, rest4ict the search to these forums as a first try.

Finally called technical support. All it took was to reset the app as well the Sonos. Working fine now. Thanks so much for all you guys help!!