When using microwave it suddenly would not shut off on its own after alarm sounds 4 times keeps running and won't shut off on its own. I have to open the door for it to shut off. Otherwise it runs until it shuts down and can't start until it comes back on by itself while door is shut. So in order to use it I have to shut the door set it by time example 2 min button wait for alarm to go off and then open door to stop it from running continuously