QR Code Troubleshooting
Almost every QR code failure is one of six things: too small, too low-contrast, cropped too tight, too reflective, damaged, or pointing at something that no longer exists. This guide works through them in the order that costs least to check.
It does not scan at all
- Size — measure the code and compare it against 1 cm per 10 cm of scanning distance.
- Contrast — dark modules, light background. Inverted codes fail on older cameras.
- Quiet zone — is there blank space on all four sides, or has artwork crept in?
- Glare — glossy laminate, glass, or a printed code under a spotlight.
- Damage — creases, scratches, water marks, or a code wrapped around a curve.
It scans only on some phones
That pattern almost always means the code is marginal rather than broken: it is readable by the better camera and not by the rest. Re-generate it with a shorter payload so the pattern is less dense, print it larger, and replace any inverted colour scheme with dark-on-light.
It scans but opens the wrong thing
- Check for a typo in the URL — a missing character or an extra one.
- Check the protocol: https:// rather than a bare domain, so it opens a browser rather than a search.
- For a dynamic code, check the destination in the dashboard — a redirect may have been changed or repointed.
It used to work and stopped
If nothing changed physically, the destination probably moved.
- The page was deleted or renamed, or the domain lapsed.
- A dynamic code's plan ended, so the redirect stopped.
- A third-party shortener that the code depended on shut down.
- The code was printed over, painted over, or faded in sunlight.
Fixing it without reprinting
If the code is dynamic, fix it in the dashboard — the printed code does not change. If it is static, you are reprinting, so use the opportunity to size it properly and think about whether static was the right choice.
Stopping it happening again
- Test a printed proof on two phones before every run.
- Write the destination URL next to the code as a fallback for anyone who cannot scan.
- Keep the destination under your control — avoid third-party shorteners.
- For anything printed in volume, use a dynamic code so a mistake is editable.
Frequently asked questions
Why will my QR code not scan?
In order of likelihood: it is too small for the distance, there is not enough contrast, the quiet zone has been cropped, a glossy finish is reflecting light, or the print is damaged. Work through them in that order.
Why did my QR code suddenly stop working?
If the physical code is intact, the destination has usually changed: the page moved, the domain lapsed, a shortening service closed, or a dynamic code's plan ended.
Can I fix a printed QR code without reprinting?
Only if it is dynamic — you change the destination and the printed code stays the same. A static code is fixed at print time, so a mistake means a new run.
Does screen glare really stop a QR code scanning?
It can, because the camera sees a bright reflection instead of the pattern. Matte materials and positioning away from direct light solve most cases.
My QR code scans for me but not for customers — what is different?
Almost always a marginal code plus a different phone or angle. Test on a second device, from the real distance, in the real lighting before assuming anything else.
Start again, properly sized
Generate a fresh code and check the size and contrast before you print.