Some factors that might contribute to this:
The size of the barcode is too small.
The environment is dark, or not bright enough.
The scanner is moving and not standing still causing a poor camera focus.
As you may notice, scanning barcodes on the web browser is not as good as other native mobile apps. This is a technical limitation within the operating system regarding camera access. Unfortunately, there is not much we can do to resolve this (other than building a native mobile app, which is not on our product roadmap).
๐กTip
Some users have reported in their tests that they found the minimum size is around 0.8โ by 0.8โ (2x2cm). Also, they reported problems reading codes printed by a direct thermal printer. While inkjet-printed labels had no issue.