Welcome to the Apple Community.
Unfortunately, a number of users appear to have encountered this problem. Some of these users have reported that the problem just disappears the following day or shortly after. Other users have found various other solutions to this problem.
Firstly, are you receiving any date and time errors when you turn on your Apple TV?
Check that you are properly connected to the Internet, by ensuring that you have a proper IP address and not one starting with 169. Also check that your location for the iTunes Store is set correctly, if so you might try changing it and then changing it back.
If the problem persists try restarting the Apple TV by removing ALL the cables for 30 seconds, or resetting it using the reset option under general. You should also try restarting your router, or if this doesn't work you might like to try a restore.
The remote control that comes with your Apple TV can also be used as a remote control for a Mac. If your Mac is in the same room as the Apple TV, you may be accidentally controlling both at the same time.
On your Mac, open up System Preferences and type "remote control" in the search box, then choose "disable remote control" to stop the Mac from responding to the remote control.
But if sometimes you do want to use the remote with the Mac, you'll either have to be careful about where you point it, or get another remote and "pair" one with the Mac, one with the Apple TV.
Yes Joseph's answer is usually the correct one - I get the impression Winston might be answering a different question!
If you have more than 1 remote you can also 'pair' the devices with their own remote.
An unpaired computer/AppleTV works with any Apple remote - when paired the device only responds to the paired remote (which transmits some kind of identifying code as well as the command), but the remote will still control unpaired devices that ignore the identifier.