Found a bug or a wrong claim?
Open an issue on the GitHub repository. That is the fastest route, it is public so others can find the same answer, and it is where fixes actually happen. If a code made here does not scan on a specific phone, say which content type, which phone and which scanner app — the same information a test needs.
If you would rather not use GitHub, the author can be reached through charlymtz.com.
Things that are not a bug
A printed code that stopped working because the destination page moved is not something this site can fix — the code still says exactly what it said on the day it was made. Point it at a URL you control next time; the static-vs-dynamic page explains how.
Requests for scan tracking or editable destinations will be declined kindly. Both require a redirect server, which is the one thing this site promises never to be.
Business, press and licensing
The generator is free for personal and commercial use, with no attribution required. There is nothing to license and no partner programme. If you want to write about the site, everything worth quoting is already on it, and the source is public.