If you see a continuously flashing status light, that indicates a failure to start up properly. Normally first try a cold restart (disconnect from power for a minute or two). If that doesn’t improve it, then the system software may need to be re-installed externally. Unfortunately, for the 4K models, users can’t do this themselves. Instead, contact Apple Support for assistance. But for the Apple TV HD (4th generation) A1625, users can restore the system software themselves through a USB-connected computer (not the network connection!).
Restore your Apple TV - Apple Support