bimetal flame sensors like that can degrade over time especially if they are in the vicinity of your washer/dryer. if you use dryer sheets or fabric softener the waxy component of them can build up on the sensor. add in lint and dust and the sensor life can be cut drastically.

couple of old HVAC techs told me that you can get by in a pinch by rubbing a newish dollar bill along the sensor to clean it off. it’s just abrasive enough to clean it and lint free enough to not leave anything behind.

might buy you a couple days to a couple months depending on how badly damaged the sensor is.

the best solution is to properly vent your dryer or move it entirely away from your HVAC unit.