QR code opens the wrong link or a 404

Decode the code first to see the string it actually contains. If the string is right, the problem is the destination: a deleted page, a retired shortener, a DNS filter, or a captive portal. If the string is wrong, the code was generated from wrong input or was tampered with physically.

Step one: read the string

Use our scanner to decode the code and display the raw text. Everything else follows from what that string is.

If the string is wrong

The code was generated from wrong input. A typo, a missing https://, a URL copied with trailing whitespace or an invisible character. Regenerate from a copied link, never a typed one.

The code was tampered with. A sticker over the original — the standard quishing attack, common on parking meters, payment standees and restaurant tables. Feel the surface for a raised edge. If it is a payment code, check the payee name your app shows against the printed one.

A design tool mangled it. Codes that have been traced, redrawn, mirrored or flattened with transparency can decode to garbage. Regenerate rather than repair.

If the string is right but nothing loads

Symptom	Cause	Fix
404	Page deleted or site restructured	Add a redirect at the old path
Domain not found	Domain lapsed	Renew, or reprint
Shortener error page	Service retired or link pruned	Never use third-party shorteners on print
Blocked by network	Corporate DNS or safe-browsing filter	Use your own domain, not a shortener
Redirect loop	Misconfigured redirect chain	Check for a rule pointing at itself
A login page	Captive portal on guest WiFi	Whitelist the domain or advise cellular
Store page instead of the app	Store link where a deep link was intended	Use a Universal Link / App Link

The lesson for next time

Print codes should point at a stable path on a domain you own, and that path should have a permanent redirect you have documented. The most common cause of a dead printed code is not the QR standard failing — it is a site rebuild years later removing a redirect nobody recognised.

FAQ

How do I see where a QR code goes without opening it?

Decode it with a scanner that displays the text rather than following it. Both iOS and Android also show the URL on a preview banner before you tap.

Why does my QR code work at home but not at the office?

A corporate DNS or web filter is blocking the destination — most often a third-party link shortener, which filters commonly block wholesale. Use your own domain.

My printed code goes somewhere I did not choose. What happened?

Either the code was generated from wrong input, or someone has physically pasted a different code over yours. Check the surface for a sticker edge, especially on payment or parking codes.

How do I stop a printed code from 404ing later?

Point it at a stable path on your own domain and keep a permanent redirect there. Document the redirect so it survives future site rebuilds.