Apple TV 3 suddenly stopped AirPlay - SOLUTION FIX FOUND

Hello all, after a power outage, for some reason I was having some trouble with my wi-fi network where I have an AirPort Express for AirPlay only, connected to my main router/wifi modem, an Apple TV 3rd gen, security cameras, iPhone, MacBook Pro, etc... In the middle of the wi-fi trouble shooting, my Apple TV suddenly disappeared for good from the network, and the whole trouble became a nightmare, of course, because I didn't think the Apple TV could have been also having a parallel problem of its own. So, after long nights of troubleshooting, I realized the Apple TV by itself was no longer available in the network as a streaming target. And it was also not letting me log my my Apple ID any longer. However, it did allow me logging to the iTunes Store with the same credentials! But it still did not show available for AirPlay.

After A LOT of research online, I saw some people mentioning the 3UTools app solution. I was a bit hesitant, since everything was working fine before the power outage. So how could it be that I would suddenly need a hardware "reprogramming" ? I was about to give up and to realize Apple had sent an invisible message to my Apple TV 3 to make it obsolete on purpose... so, since all I had was a bricked Apple TV 3 hardware... oh well, not really bricked because it was booting and showing on TV, but if its apps weren't working and neither was AirPlay, it had no use whatsoever... so I decided to try 3UTools...

Downloaded the 3U app onto an older MacBook Air, connected the USB port to the Apple TV 3... and ran a "batch activate"... connected the Apple TV back to the TV via HDMI, and BAAAAAAAMM! I had AirPlay back working EVEN BEFORE CONNECTING THE APPLE TV TO THE NETWORK !!!

That said, I still wasn't able to log the Apple TV back to my Apple ID. But AirPlay is just working perfectly again, EVEN IF THE APPLE TV IS NOT ON ANY WIFI NETWORK. The phone connects and streams directly to it via wifi.

I hope this post helps many people struggling as I was until I found this solution.

Disclaimer: the fact that it worked for me, unfortunately does not mean it will work for everyone's case scenario. Troubleshoot it at your own risk! Best of luck!