A few things to do.
Number one, Test your network connection.Just in case, restart your modem and if you have a router do the same. If the Apple tv is communicating Wi-Fi and not direct via a ethernet cable, go to airport utilities and make sure your Airports are up to date if not do and update and restart your airports.
Number two, Disconnect from power ur apple tv for 10 seconds.
Number two, reset to original settings your apple tv reenter passwords id and do updates.
Number three, do u have more than one apple tv? If yes do the same with all you have at the same time. If they are in different locations, have someone just disconnect and reconnect the power on them.
I had the same problem and NO ONE AT APPLE KNEW HOW TO SOLVE IT. APPLE IS NOT WHAT IT USED TO BE IN PEOPLE KNOWING WHA THEY ARE DOING. THE GENIUSES ARE ARE EXACTLY THAT "GENIUSES". Last night a tech support from the 800 2752273 couldn't answer a very simple question, I had to laugh and he got upset and hanged up the phone on me. His name is Alfred and works in the iOS division.
I solved the problem like this because one Apple tv in a remote location was either hanging a process of and auto update or some other process.
Last you go to the iTunes Store, go to your ID and just reenter your credit card and verification code and expiration date.
If you can watch movies or listen to music not from purchased but from your library, it is very likely that one or more apple tv's are hanging the connection.
I can tell you that since Yosemite was released, it is the most buggy system I have ver dealt with.
Memory leaks, crashes, the simplicity of Apple has disappears, now we are all driving a Windows system with the looks of Apple and not even so beautiful.
Also iOS is very messy.
I hoe a lot of fixes and come very soon. Yosemite ***** BIG TIME!!!