Oven won't light, push preheat button and board displays preheat but it doesn't attempt to light, ignitor does not heat up. The display just gos off in a few seconds, press it again and it does the same thing, Turned off power to oven for a few minutes and retried and it worked ok, but when I turned it off, let it cool down and tried it again it went back to only showing the preheat display a few seconds and then going off again