Why did my QR code stop working?
A QR code that worked yesterday and fails today almost always has one of six causes. Most can be found in a few seconds, and all of them can be fixed.
1. The free trial ended
Many QR code websites give you a dynamic code: it holds their own short link, which forwards people to your page. When a trial ends, often after 7 to 14 days, or a subscription lapses, they switch that link off. Every printed copy stops working at once, even though the print looks fine.
2. The short link was deleted or expired
Codes made with a link shortener depend on that short link. If it's deleted or expires, or the account behind it closes, the code leads nowhere.
3. The website behind it changed
If the code points straight to a page that has since moved or been taken down, it still scans but the page is gone. The code itself is fine; the address inside it needs updating.
4. It's printed too small
Phones need enough detail to read a code. As a rule of thumb, print it at least 2 cm wide, and bigger the further away people stand: about a tenth of the scanning distance.
5. Not enough contrast
Light codes on dark backgrounds, pale colours, busy photos behind the code or a shiny laminate can all stop a phone reading it. A dark code on a light background is the safest choice.
6. Damaged or covered
Scratches, folds, a sticker over a corner or a logo that covers too much of the code can leave too little for the phone to read.
How to find out which one it is
Take a photo of the code, or paste its link, into the free checker. It reads the code, shows what's inside and tells you whether it depends on a trial or a short link that can be switched off.
How to fix it for good
If the code depended on a trial, make a replacement that holds your link itself, with nothing in between to switch off. Print it as a sticker over the old code, so you don't have to reprint everything.