Diagnosis
The thermal fuse or thermal cutoff has blown. This is a safety device that trips if the unit overheats.
How to Fix It
First, check your kitchen's circuit breaker or GFCI outlet. Plug the unit into a different outlet. If it's still dead, the internal thermal fuse has likely failed. This requires disassembly to access and replace the fuse, which is not a user-serviceable part.
If That Didn't Work
If the unit has power (control panel lights) but won't heat, the main heating element may have burned out. You can visually inspect it for breaks through the top vents when unplugged.
Heads Up
Do not attempt to bypass the thermal fuse. The unit overheated for a reason—blocked vents, faulty thermostat, or a stuck relay. A repair tech must diagnose the root cause.