I\’ve had MS Lumia 950xl dual sim for about a year. Only 3 times could I sign in with that.
I use it often. The trick is to be sure to look at the camera. Although the infrared light is in the left corner, the camera is in the right one. If you can see your reflection of your eye on the surface of the phone, you can move the phone until your eye is over the camera. Once you know where to look, it works quite well.