I would first double press the home button on the remote and swipe up all/if any programs and restart the Apple TV.
Then open to see if the problem(s) are still happening. If so, I would shut modem down and unplug and do the same to the router, I also shut down computer. After about 30 seconds or so, plug in modem, turn back on and wait until the modem lights are a go. Do the same for the router and turn on the puter. When, I go through those steps for the same issues all is go to go till the next time
It only takes a few minutes and for me, it's no big deal.