Why is this marked as solved if it isn't working?

I use code from here:
https://m5stack.com/products/mini-heart-unit
Arduino IDE

Hello! My heart rate unit is working with m5stack, but it dosen't work with m5stick. Code is the same. When I turn on m5stick sensor flashes for about 0.5 second and then remain dim, so serial monitor return 0 for forever. What is the problem? Thanks.