Make QR practical guide
Why Your QR Code Is Not Scanning: A Checklist
First separate two problems: a reader cannot decode the pattern, or it decodes a link that fails to open. They have different fixes. Use the original exported image and then test a physical proof, instead of relying on a cropped screenshot.
If the reader cannot decode the code
Check that the corner finder patterns and white border are intact. Restore the quiet zone if the image was cropped, and remove text or artwork placed over it. Try a dark, solid module color on white to isolate a contrast issue. Avoid stretching the image or taking a small screenshot and enlarging it.
Reduce or remove a center logo, especially if it has fine details. Try a simpler module pattern, a larger print size or a higher-resolution PNG. SVG can preserve sharp modules when scaling. Shortening an unnecessarily long URL or removing unused contact fields can reduce the code's density.
If the reader finds a link but the page fails
Open the exact encoded URL yourself, preferably in a private window. Check for spelling mistakes, expired domains, deleted files, permission restrictions and pages that require a login. A QR reader cannot make a private document public or repair a broken destination.
For a Wi-Fi code, verify the case-sensitive network name and password and match the router's security type. For a contact or email code, test the phone's contacts or mail application. Some readers display raw data rather than offer an action, so try the intended device's native camera as well.
Test conditions matter
Move the camera closer or farther away so the code can focus. Improve lighting and avoid reflections on glossy signs. A curved package may distort the pattern, and a distant wall sign may need a much larger code than a business card. Test with more than one phone when the artwork is meant for a wide audience.
Make QR's scanner can read an uploaded QR image in the browser and show the decoded data. It is a useful check, but passing one scanner does not guarantee every camera and print condition. Always scan the actual exported file and a final-size print proof before distributing it.