I'm having same problem with my X92 android box , won't let me stream any live tv... mine won't even work using Enthernet cable , like you have said I use to have Internet threw telephone line running 10mbps and it work , it even works off my 4g on my phone , I've an engineer coming out Thursday will let you know how I get on
Welcome to the community I'm sorry to hear your Apple TV isn't working over wifi.
What exactly is happening when you try to connect the box to your wireless network? Do you get any error messages at all? It might also be worth setting up a guest network and testing a few different security settings to see if any of these allow the box to connect. I'd also check that the box's software is up to date, though I'm sure it already is.