This is caused by the power supply detecting an over current condition. The condition could be a bad LED in the back lights. Since you did not post the exact model number, that is all.
If your TV turns itself on and off that might most obviously be due to temperature and otherwise, to time.
Since temperature is the most obvious cause, what happens if you move things around so there's a lot more space on all sides of the TV? What happens if you add at least two inches up, down and sideways?
