I purchased an IR height sensor from E3D. However, I believe it to be faulty because despite the LED flashing four times, it doesn't trigger when I put my hand underneath it.

Here is a video to demonstrate the problem
https://drive.google.com/file/d/1S55BfL8XKh5kCKQlZ6t4E9QOYAN7mBoA/view?usp=sharing

https://drive.google.com/file/d/1pSkJj-lVJO_I8RXVOtWzrVn7tdQCMrXO/view?usp=sharing