# A code won't scan (Help)

URL: https://qrdx.dev/docs/help/troubleshooting/wont-scan
Source: https://github.com/bucharitesh/qrdx/blob/main/apps/docs/content/docs/help/troubleshooting/wont-scan.mdx

Why a QR code isn't scanning, and how to fix each cause.

If a phone camera doesn't react to your code, or reads it only sometimes, work through these checks.

Start with the **Scan score** under the preview in the [playground](https://qrdx.dev/playground). Click it to see which checks fail. See [Check a design with the scan score](https://qrdx.dev/docs/help/designing/scan-score).

For a code that's already printed, take a photo and drop it into the [scan checker](https://qrdx.dev/tools/scan-checker). It shows what the code says and tests how well it reads.

## Common causes [#common-causes]

### Low contrast or light on dark [#low-contrast-or-light-on-dark]

Scanners look for dark squares on a light background. Make the code darker or the background lighter, and avoid light codes on dark backgrounds. See [Choose colors that scan](https://qrdx.dev/docs/help/designing/colors-and-contrast).

### A logo covers too much [#a-logo-covers-too-much]

Set **Error correction** to **High** in the **Design** tab. See [Add a logo](https://qrdx.dev/docs/help/designing/logos).

### Unusual eye shapes [#unusual-eye-shapes]

Circle and curly corner eyes fail in some scanner apps. Square, rounded and gear eyes read everywhere.

### No clear border [#no-clear-border]

Scanners need empty space around the code. Set **Padding** to **Standard** or **Large**, and don't let other artwork touch the code.

### Printed too small [#printed-too-small]

Make the code about one tenth of the scanning distance: 2 cm for a card read at 20 cm, 10 cm for a poster read from 1 m. The [print size calculator](https://qrdx.dev/tools/print-size) works it out for you.

### Too much content [#too-much-content]

A static code that holds a lot of text becomes dense and hard to read when small. Use a dynamic code instead: it holds only a short link. See [Static or dynamic](https://qrdx.dev/docs/help/getting-started/static-vs-dynamic).

### The print itself [#the-print-itself]

Blurry printing, glossy surfaces that reflect light, and curved or folded surfaces all make codes harder to read. Print as a vector file (SVG, PDF or EPS) and test one copy before printing many.

## It scans, but shows an error [#it-scans-but-shows-an-error]

If the camera reads the code but you see a page like "QR code not found", see [A scan shows an error page](https://qrdx.dev/docs/help/troubleshooting/error-pages).