What it it Error: 301003?
error 301003 apple tv
Apple TV 4K, iOS 12.1
If the setup fails, you could get that error. It may not find a network or connect to it. If you tried automatic using an iOS device, then try manually entering the settings. If indeed you are setting up a new device for the first time, and it won’t work while following the instructions (don’t use a captive network, because that is not supported), then try another network (neighbor, Apple Store). If the Apple Store can’t get a new device to work, then you may want to exchange it for a functional one.
Set up your Apple TV - Apple Support