Unable to detect a specific QR code

[wywong20]

Description of the problem:

I have a QR code that can't be detected easily. It is just a simple QR code but I need to move the phone far away to detect it successfully (not work every time) whereas I can scan other codes instantly. My app has been run for 3 years and this is the first time I can't scan a QR code. I don't understand what the problem is. Please help. Thank you.

Which library version are you using? E.g. 3.2.0.
4.1.0

Which phone/tablet are you using, and which Android version does it run? (e.g. Samsung Galaxy S5,
Android 5.0)
Google Pixel 4a

Does the same happen on other devices or an emulator?
Yes

This is the QR code I can't detect easily.