Barcode production guide
Why is my barcode not scanning?
Troubleshoot barcodes that will not scan by checking data validity, quiet zones, contrast, image scaling, print size, resolution and the barcode format.
Check that the value is valid for the selected format, keep dark bars on a light background, preserve enough quiet space, avoid stretching the image and print at an adequate physical size. Code 128 is a safer fallback for mixed letters and numbers.