GM_60 QR Reader not working at all

I tried with 

Arduino Nano 33 IoT

D1 Mini

Raspberry Pi zero w

(with uart and i2c)

I've tried connecting it to multiple devices, but there is no response other than the LED slowly changing color. 

Unlike the operational videos on YouTube or the product description page where the LED flashes rapidly when a QR code is presented, my device shows no such reaction.

https://github.com/DFRobot/DFRobot_GM60

I have tried all the sample codes on this page, but nothing has been successful. 

I'm not sure if it's a malfunction or if I've made a mistake.