If you have an iPhone, we would recommend using the QR code reader app: QR code or QR scanner.
If you have an Android phone, we'd recommend using the app: Lightning QR Scanner. It could be downloaded here:
apps/details?id=com. application_4u.qrcode.barcode. scanner.reader.flashlight&hl= en_GB
On the other hand, if you happen to have a WeChat account, it has a pretty solid QR scanner too.
When you are scanning the QR code, it is recommended to try zoom in, zoom out, and adjust the angle, so the QR code reader will work better. Sometimes the lighting effects as well.
We hope this is helpful.