Same here, iPad doing fine after update to iOS 6 but iPhone 4s(updated from beta 4) is getting page not found. Thought wifi password was wrong but I don't think so. I will wait for all the Apps to finish reinstalling and then restart.
Non-upgrades iPad 2 is still funtioning fine, the New iPad that just got updated to iOS6 is doing this. I noticed it stopped downloading updates and tried to restart, now getting this error. I do not need a bricked iPad (no network might as well be bricked) it's hard for me to get work done.