Hi. I just got a new router -- Linksys EA3700, which is an AC1750 (802.11ac). My previous router was 802.11n. I have followed the Sonos setup instructions for getting a new router, i.e., plug one of my Sonos speakers into router via ethernet cable and then go to Advanced Settings -> wifi setup. This setup asks for the password for my new router. Upon doing so, I just get the error: "Wireless problem! Please check the name and password for your network. Ensure you are using a 2.4GHz wireless network that is compatible wiht 802.11b/802.11g."
I have followed advice of the some of the forums to shut everything down and then reboot in following order: modem, router, Sonos devices, other stuff (computer, iPhone). And then I repeated the Sonos setup process above to no avail.