Hi, thank you for contacting JustAnswer.com. My name is Russell. I will do my best to provide the right answer to your question.
Your key may be defective. Usually they have a 'permanent' magnet in them, and if a magnet is subjected to sufficient mechanical shock, it will demagnetize.
Has your safety key been dropped? onto a hard surface, even once, recently? if so, it might just have demagnetized... though you can test that very easily, by trying to pick up a nail or a screw (made of iron or steel) with it, and see.
If the safety key has demagnetized, then you should replace it (they're cheap enough to replace.)
But if not... then the magnetic switch in the console is not working. That would imply replacing the console, unfortunately, which is expensive.
Let me know what you find out from the test I suggested, and I will advise you further as appropriate. Thanks.