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QR Code Not Scanning? A Practical Troubleshooting Checklist
Diagnose a QR that won’t scan by checking recognition, print quality, quiet zone, contrast, size, surface and the decoded destination.
4 min read · Updated October 11, 2026 · How these guides are prepared
In this guide
First find out whether the phone can’t recognize the QR, or recognizes it but can’t open the destination. Recognition problems usually involve contrast, a missing margin, image quality, density or the physical surface. Link problems need checks of the URL, the hosting, the link’s settings and the account.
Start with a two-stage test
Open the camera or a trusted scanner and note what happens. If it never detects a symbol, the problem is probably the image or the reading conditions. If it shows an address that then fails, the QR may already have scanned correctly.
Test the same exported image on a screen and on the printed item. A result on screen helps isolate a printing or placement issue. Try another phone too: a single device can hide a marginal design that fails elsewhere.
Check the image before changing the link
| Symptom | Check first | Practical next step |
|---|---|---|
| Nothing detected | Margin, contrast, blur, distance | Export a clean file at a usable size |
| Works on screen only | Printing, surface, lighting | Test a final-size proof in place |
| Address appears but fails | Destination and link settings | Open the decoded address directly |
| Works on one phone only | Marginal size or reading conditions | Test other devices and simplify |
Keep a clear quiet zone around a standard QR symbol: DENSO WAVE specifies four modules on each side. A decorative border, a caption or a crop that eats this space can stop recognition even if the code looks balanced.
Use dark modules on a light background and keep the export sharp. If the code was enlarged from a small screenshot, go back to the original file. A printer’s resizing and smoothing can blur otherwise clean edges.
Simplify decoration and account for the surface
A logo should never hide the key structural parts of a code. Error correction is not permission to cover any area you like; it recovers damaged data within limits that depend on the symbol and the damage.
Glare, curves and viewing angle also reduce readability. Test a glossy card under the venue’s lighting, or a label on its final container. Move the phone and change the angle to see whether the material causes a consistent problem.
If scanning works, check the whole destination
Look at the decoded address and open it directly. Check the protocol and the domain. See whether the page has moved, needs a login or is down. A recognized QR doesn’t bypass the page’s own requirements.
For a dynamic code, check the right account and workspace. Look for a pause, an expiry date, a password, a scan limit, a scheduled destination or a routing rule. Don’t generate a new image before you know which part of the journey failed.
Retest a finished proof before replacing a whole batch
Keep the working file and the placement details with the campaign record; a later reprint or investigation will be easier. A new menu link and a new printed graphic are different changes, so note which one you made.
If an unexpected QR leads to a sign-in or payment request, check the address before continuing. The FTC advises inspecting unfamiliar QR destinations and being careful with urgent, unexpected messages.
Questions, answered
Can a QR be too small?
Yes. Readability depends on module size, data density, print quality and distance. Test your design rather than relying on one universal size.
Can I cover 30% of any QR with a logo?
No. Error-correction percentages are not a safe rule for overlays. Keep decoration within the designer’s checks and test the final code.
Why does the code scan but show an unavailable page?
Recognition and destination availability are separate. Check the decoded URL and any hosting, account or link settings.
