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- First you should try logging out of your iTunes Store account (settings > iTunes Store > accounts) and then back in again.
- If that doesn't help, try resetting the Apple TV (Settings > General > Reset > Reset all settings). You should also try restarting your router.
- If both of the above don't help, you should try a restore (Settings > General > Reset > Restore).
This ended up helping me out as well. Just bought a MacBook Pro and the same day I came home with it, Apple TV asked if I wanted to do an update. For a moment I thought maybe I did something to my iTunes account by setting up my MacBook. Long story short, I signed-in and out of iTunes on AppleTV, reset my router, but the cure ended up being resetting my appleTV all together again.
Thanks for the help. now I can get back to watching Breaking Bad!!!