I too am struggling with Netflix. I can access any other channel on my ATV3 without trouble, but Netflix just sits and spins, with the "Accessing Netflix" on the screen.
I used to reboot it at that point with mostly, but not always, success.
Now, I let it time out, and it says something to the effect of, "Netflix cannot be accessed at this time, please try again later." From there, I click the back button, which takes me to the main ATV screen. I click on Netflix, and everything is good.
Odd bug.
I'm not sure whose fault it is.