Diagnosis
The projector is in a hard protection lockout, usually triggered by overheating or a power fault during its last shutdown.
How to Fix It
Unplug the power cord from both the wall and the projector. Wait a full 5 minutes for internal capacitors to discharge. While it's unplugged, check the air intake and exhaust vents for any major dust blockage. Plug it back in directly to a wall outlet (not a power strip) and press the power button.
If That Didn't Work
The internal temperature sensor or power board might be faulty. Try a different, known-good power cable first. If no change, the unit likely needs service.
Heads Up
Never move or unplug the projector immediately after turning it off. Always let the cooling fan run to completion, which can take a minute or two after the light goes off.