Microwave turns on when you open the door how to solve this fault

When a microwave oven turns on when you open the door, it is because one of the door switches is failing, normally it is because the points of the switch are burned and it stays stuck.
With a multimeter you can test the continuity of the switch circuit, when you open the door you have to open the circuit and turn off the rotation motor and the magnetron and you only have to turn on the focus, if the rotation motor and the fan and the magnetron means that there is the fault in the switch that has been stuck