Apple TV not responding

Our Apple TV suddenly stopped responding. It will turn on to the home screen via the remote but does not respond at all to commands from the remote. We replaced the remote battery just in case, we've plugged/unplugged the Apple TV from our Samsung TV. Nothing, no response. (I'm not sure what generation the Apple TV is, btw. ) It also stopped responding to screen mirroring from my iPhoneX, although the phone indicates that it is connected and mirroring. Any ideas/suggestions? We're not terribly tech savvy so the less complicated suggestions, the better! Thank you.