Diagnosis
It's most likely a safety lockout from a recent power surge or a full internal reservoir, not a dead unit. These have protection circuits that need a manual reset.
How to Fix It
Step 1: Unplug it from the wall. Step 2: Pull out the water bucket. Step 3: Leave it completely unplugged and with the bucket out for a full two minutes—time it. This drains any residual power and resets the main board. After two minutes, plug it back in firmly, then slide the bucket all the way in until it clicks. You should hear the startup chime and see the display light up.
If That Didn't Work
There's a small chance the fuse in the plug (if your model has one) blew. Check the plug itself for a tiny fuse compartment. If you find one, replacing that 5-amp fuse might do the trick.
Heads Up
Never bypass any internal fuses or try to jump-start the unit. If the full reset doesn't work, it points to a board failure that needs professional service.