Morning jagrell,
Thanks for using Apple Support Communities.
For troubleshooting on this, take a look at this article:
Apple TV (2nd and 3rd generation): Troubleshooting Wi-Fi networks and connections
http://support.apple.com/kb/TS4546
For more information on this, take a look at this article:
Apple TV: Troubleshooting wireless connections
http://support.apple.com/kb/ht1595
For more information on this, take a look at this article:
Apple TV: Basic troubleshooting
http://support.apple.com/kb/ht1551
Best of luck,
Mario