This is an issue with the update, an ambassador will likely w get on here and tell you to clear the casche off your Xbox and then they will tell you to uninstall and reinstall the update, then they will tell you to redownload load your profile.
Maybe even tell you to open up your nat settings, or turn on your upnp settings on your router. One of these may actually give the appearance that it is working again, but it won't, and is sure to start acting up again. Unfortunately this has been going on for a couple weeks and M$ has not done anything or acknowledged an issue. The hope is they will fix this SOON but I'm not holding my breath, just hoping for some sort of compensation at this point since I am now paying for nothing