Mark Gurman, 9to5Mac:

Apple has informed its official retail stores, AppleCare employees, and authorized resellers that a small number of third-generation Apple TV units have WiFi issues. These issues surround not being able to locate a WiFi network, unable to join a network, and dropped or intermittent connections.

If you’ve been having trouble keeping your Apple TV on its wireless network connection, check the link for details to see if yours is one of the afflicted models.