Apple

So I just picked up an Apple TV (Brand new) from Best Buy and hooked it up to my Samsung QN90A and it immediately started flickering at me (the entire screen would go black then show the picture and go black again in a continuous cycle) it would go away when I opened the settings app and the only fix I’ve found so far is unplugging the tv and Apple tv and hooking them back up together for them to shortly start the process all over again, I don’t think it’s the Apple TV because I work at Best Buy and when I bought it we hooked it up to one of the display TV’s and just let some movies play throughout the day but I have no idea what is happening right now, any ideas?