Why your QR code is not working
Most pages on this subject are a list of twenty or thirty possible causes, which you are left to work through on your own. You do not need the list. Four questions, asked in this order, narrow it to the actual fault, because each answer rules out whole categories before you spend money on the next.
Troubleshooting4 min read
Does the phone react to it at all?
Point a camera at the code. If nothing appears, no banner, no link, no reaction of any kind, then the pattern is not being read, and the fault is either physical or in the file the print was made from.
Split those two apart with one test: scan the original digital file on a screen.
- If the file scans and the print does not, it is a print problem. The usual causes are a code printed too small for the distance it is scanned from, the pale quiet border trimmed off, weak contrast between the squares and the background, a logo covering too much of the pattern, or glare off a laminate. The print guide has the numbers, including the minimum size in millimetres.
- If the file does not scan either, the code was generated faulty. Two causes cover nearly all of it: too much text packed into the code, which makes the individual squares too fine to read at any sensible size, and inverted colours, because light squares on a dark background defeat many readers. Regenerate with a short address and dark squares on a light background, and test it before anything goes near a printer.
Does it scan for you but not for other people?
Then the code is fine and the destination is conditional. It opens for you because you meet a condition other people do not.
The usual conditions: the page only exists on your office network or behind your VPN; the link opens an app that only you have installed; the code points at a staging or preview address rather than the live one; or the destination is a file in a personal cloud drive with sharing never switched on. That last one deserves saying twice, because the file opens perfectly on the phone of the person who owns it and on nobody else’s.
The test is one step. Open the destination on somebody else’s phone, on mobile data, signed out of everything. Whatever fails there is the fault, and the fix happens at the destination, not on the code.
Does it open, but in the wrong place?
The scan works and a page loads, just not the page you meant. Three causes cover nearly every case.
- The destination moved. If the code carries your own address and the page behind it was reorganised or deleted, the code is faithfully reporting your website’s history. Fix it at the website: forward the old address to the new one. No reprint needed.
- You printed a superseded file. An old proof, the wrong artwork version, or a placeholder code left in from the designer’s mock-up. Scan the printed object itself and compare what it actually contains with what you meant it to contain.
- The code is dynamic and pointing somewhere stale. If it resolves through a short link and the destination is simply out of date, sign in to the service that made it and repoint it. That fixes every printed copy at once. If you are not sure which kind you have, the ten-second test is here, along with the options when it turns out to be the kind that cannot be changed.
Does it show an error page from a company you do not recognise?
A page saying the code is no longer active, or paused, or inviting someone to reactivate a subscription, under a logo that is not yours. This is the one branch where nothing you printed and nothing you built is broken. The code is dynamic, and the redirect service behind it has switched it off, usually because a trial ended or a subscription lapsed.
The pattern on the paper still contains exactly what it always did, so do not reprint yet. The sequence (identify the vendor from the short address, reactivate with them, then decide whether to move) is written up on its own page.
Worth knowing while you are here: this branch exists because switching codes off at the end of a plan is how most providers operate, not because it is inevitable. Our printed codes keep resolving after cancellation, and a test inside every deployment checks that they still do.
If none of the four fits
The leftovers are rare and mostly about hardware and light. Native QR scanning arrived in phone cameras around 2017, so a handset older than that needs a separate reader app. A code that works indoors and fails in the window is glare or direct sun. One that scans intermittently is right at the edge of size or contrast, and should be treated as the first branch.
Whichever branch you end up in, test the printed object, in the place it hangs, in the light it hangs in. A file that scans on a screen has told you almost nothing.
We make QR codes you can re-point after they are printed. The pattern on the page never changes, and the codes you have already printed keep working even if you stop paying.
Three codes free, no card. Paid plans start at £3.49 a month including VAT.