Solved my issue, though I'm not sure it's the only fix. I unplugged the Ethernet cable from my desktop computer, which put it onto wireless. My ATV is also on this wireless, and as soon as I unplugged my desktop computer, I could see it via Home Sharing on my ATV.
Does this make sense that the only way I can Home Share is to have both the ATV and the desktop both on wireless?
Like so many others having problems connecting Apple TV to your iTunes account via Home Sharing, I could get everything on my Apple TV to work great, with the exception of Home Sharing. I'm not a network guru, and I just could not get my Apple TV to connect to my desktop computer iTunes account via Air Play.
I am running an Actiontech router with Verizon Fios.
Last night, I did the following:
1. Disconnected my desktop computer (running iTunes) from my ethernet connection to the router; my desktop then connected to the wireless network (the same network that my Apple TV connects to);
2. Restarted iTunes, and immediately iTunes connected to Air Play, and my APple TV connected to my desktop iTunes account via Home Sharing (great!);
3. I then plugged my ethernet connection back into the desktop (hard wired back into the router), and disconnected from the wireless network; I remained connected to Air Play and remained connected to my Apple TV (Apple TV still on wi-fi);
4. If I shut down iTunes, and attempted to re-start while connected to my router via ethernet, I once again could NOT connect Apple TV to my iTunes Home Sharing account. I had to repeat steps 1-3...
Apparently, my issue is with my desktop and my Apple TV not initially connecting if they are not one the same wireless netowrk. After connecting via wireless, and putting my desktop back onto ethernet, I can Home Share with no issue so long as I don't close iTunes.
Any ideas what might be happening here? Sounds like a router config issue, but a bit beyond my troubleshooting epxertise.
Many users are having this issue.
Some routers do not broadcast Bonjour properly between the WiFi network and LAN ports - devices connected via cable to the Eth ports.
It would work if both devices are either on WiFi or are wired. Each router would have different troubleshooting steps but the general idea is to:
1. restart the router
2. upgrade the firmware of the router to the latest one.
3. Check for any specific settings on the router that would limit traffic between WiFi network and wired one.
4. Try different router. Apple's Airports Extreme and Express or Time Capsule are almost certain to work.