My nest protect starts chirping at early morning like 3-5 am. I tried to reset it by long press and it does a self test followed by " everything is fine" message. Later it starts chirping next morning. This has gone on for 1 week now and I've tried the self service methods of dusting it, resetting it etc. This is a direct powered version and not a battery one. This morning it says wifi connection problem too on top of smoke sensor failure.