My key is not sensed when inserted in the tumbler.

The car starts and runs fine, but immobilizes light on dash is always flashing. Also, using the key to program key fobs or do the key dance to reset the throttle body. The key left in chime does not chime when the door is opened and the key is in the ignition. Any thoughts on what would cause this? I assume there is a sensor to detect the key. I would think if the sensor is bad, the car would not sense the chip and the car would not start. But the car starts, It just won’t do all the things you are supposed to be able to do with the key.

Thanks for any suggestions.