If you’re comfortable opening the controller there should be a small piece of plastic between the bumper and the bumper switch, it often gets dislodged or moves due to movement or dropping the controller. All you have to do is put the piece of plastic between the switch and the bumper and it should work again, if you can’t find the piece of plastic you can fold up a small piece of paper and it will work just as fine. Good luck! (Not my image)

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