The AIr Play icon no longer consistently appears on my iMac or my iPad. Apple TV is 3rd gen, iPad is 4th gen, iMac is latest (2012) router being used is Linksys (Cisco) E3000. Opened TCP ports 123, 3689, and UDP 5353, and after saving the router settings, the Air Play icon appeared on iPad but disappeared again after less than a minute. The Air Play also appeared on my iMac and when I clicked the rainbow wheel appeared and after less than a minte the Air Play icon vanished again. I have performed restores of the AppleTV both by using the iMac with a micro USB and also did a restore while connected to the television. Any other suggestions before I take it into the local Apple store? Thanks.
I set an appointment at local Apple store Genius bar. The tech helped walk through and eliminate possible variables until we agreed it must be a problem with my router. BTW, the tech hooked up my Apple TV at the store and it worked perfectly using the Apple store network. I went home and restored my router to the factory default (like out of the box when it was new) and re-set it up. When I finished my Apple TV has been displaying the AirPlay icon flawlessly. Hopeful it will continue, but resetting one's router to factory defaults may fix your problem if you are expeiencing same issue when the AirPlay icon goes missing.