My multiple Apple TV's do not see my iMac, what's the deal?

[iMore Question]

My multiple Apple TV's do not see my iMac.

Home sharing is on in iTunes on the iMac and on the Apple TV's. I have disabled and re-enabled on both the Apple TV's and the iMac. I can airplay from the computer to any of the Apple TV's but none of the Apple TV's can see my library. Help! I am running Yosemite 10.10.3 on a late 2013 i7 27" iMac. My wireless network is using an Airport Extreme AC v7.7.3 .Oh and yes I am running the public beta but the problem was happening before that.

 

[kch50428]

Re: My multiple Apple TV's do not see my iMac.

Apple TV - AirPlay - Apple Support