What actually expired
A QR code cannot expire. It is ink on paper, a pattern that encodes some text. What expired is the service behind that text: you made a dynamic code, which means the dots contain a short link on the generator’s domain, and the generator stopped forwarding it when the trial or plan ended. Scanners now land on an error page, a "this code is inactive" notice or a sales page for the provider.
It is a common story. Most of the big generator sites show a "free" button that quietly makes a dynamic code on a 14-day trial, and the printed codes die two weeks later unless you pay €5 to €15 a month.
Confirm it in one minute
Use the scan test and upload a photo of the printed code. The decoded text is the truth. If it is a link on a domain you do not own (qrco.de, qr.io, me-qr.com, qr-code-generator.com, qrfy, scanova and so on), the code is dynamic and belongs to that provider. If it is your own link and the page is simply gone, that is a different, easier problem: fix the page.
Can the printed codes be saved?
Only by the provider. The short link lives on their domain, so only they can make it forward again, and they will do so when you subscribe. If the print run was large and expensive, one month of their plan to buy time while you reprint can be the cheapest exit. Cancel in writing and screenshot the confirmation; several of these services are known for making cancellation hard.
Do not try to "re-register" the short link anywhere else: nobody but the domain owner can serve it. Any site offering to revive another provider’s code is not telling the truth.
Reprinting: the two ways it never happens again
Either way, point the code at something you own. A static code to your own domain is the most durable object in marketing.
Static code. The content goes in the dots, nothing in the middle, nothing to switch off. Free, here, no account. Right for links you control and for Wi-Fi, contacts and text.
Lifetime editable code. One payment per code, the redirect runs for good, you change the destination whenever you need to. No plan to lapse. Right for menus, signage, packaging and anything expensive to reprint. See pricing.
Before you print the replacement
Decode the new file with the scan test and read the content.
Check the generator’s terms: does the code depend on their servers? If the dots contain their domain, it does.
Print one, scan it with two different phones, then print the rest.