My Nikon D5500 stopped recording videos. Pressing the red button didn’t do anything at all. Searching about this on the internet told me there’s a problem with the lens.
Not exactly with the lens but your camera thinks that the lens isn’t correctly attached. To fix this, simply remove the lens and attach it correctly as follows:
Press the lens-release button and while that’s pressed, just
position your lens on the camera and rotate it like one degree or so. Then
release the lens-release button such that it’s no longer pressed.
At this point, rotate the lens completely and attach it. You should hear a click or snap or whatever which tells that the lens is in place. Turn on the camera now and press the red button and you’ll have your video recording feature back 🙂