Did YouSee work before on your system? There is no indication of an issue at status.sonos.com, but I can’t verify this as it isn’t available here in the US.
I’d check your account on www.sonos.com and make sure your location is set properly. I’d then uninstall it from my Sonos system, wait 5 minutes, then add it back to your Sonos system. If that doesn’t ‘fix’ it, I would call Sonos Support directly to discuss it.