I haven't had any issues with the Apple TV and iOS apps for a week, but lately its been having issues showing the availability of the computer I use to store the files. For example if I'm browsing the contents on the Apple TV, then go back to the main menu of the Apple TV app, it shows my computer no longer being available when I was just using it. I'll have to exit and enter the app a few times before it will show up as being available again. I think the issue is something with the server app not broadcasting quickly/frequently that it is there.
Some network info:
Apple TV: Ethernet connected
Server Machine: Ethernet connected, OSX 10.11.2, Air Video Server HD 2.2.2
Both machines have DHCP reservations so they have a static IP address.