This is different than my iOS problem…
I took my ATV off my home network and am running it off of my hotspot. I am asked on the ATV to goto http://ip-address/auth...but that URL gives me an error “Could not connect to the server”
Are you using port 57000 in the url? You need to visit that url from another device on the same Wi-Fi network, and the Wi-Fi must allow peer to peer connections.
I was using my personal hotspot on my iphone…and going to that URL from my iphone. From what you are saying it sounds like that was not a valid test.