1 The thermistor is broken and does not generate heat.

2 The coil disc is damaged and not heated.

3 The power cord is short-circuited. Open the circuit without heating.

It is very convenient to disassemble the heating pot and process a screw.

First, visually inspect the damaged area. If no problems are found by visual inspection, use a multimeter. There are few devices at the bottom of the pot, and problems are quickly found.