If you have a QR code identifier, use the following tips to improve QR readability:
make sure that there is no protective film on the panel camera;
the code must be valid when it is used;
sunlight must not fall on the camera;
keep the code at the same horizontal level as the camera;
the distance between the camera and the code must be 25-40 cm;
hold the identifier in a stationary position for 5 seconds.