Support
QR Zen is made by one person, and email reaches him directly. Expect a reply within a couple of days.
Contact
For a bug, it helps enormously to include your device model, your iOS or Android version, and the app version from Settings → About.
The camera shows a black screen
The app needs camera permission. On iOS open Settings → QR Zen → Camera; on Android open Settings → Apps → QR Zen → Permissions. If the permission is already on, closing the app fully and reopening it clears most camera-in-use conflicts with other apps.
A code will not scan
Give it more light and hold steadier — most failures are focus, not the code. Damaged or very small printed codes may need you to move closer. If the code is on a screen, raising that screen's brightness usually fixes it.
A code I made will not scan
Check the contrast line under the preview. Light modules on a light background, a logo covering too much of the centre, or a very long payload each make a code fragile. Raise the contrast, shrink the logo, or shorten the content, and always test the printed result before producing it in bulk.
Where did my history go?
History is stored only on the device, with no cloud backup. It does not survive uninstalling the app, moving to a new phone, or clearing the app's data. Export anything you need to keep.
Requesting a feature
Worth asking — the roadmap is mostly driven by what people write in about. Tell us what you were trying to do, not only what you want added; it usually leads to a better answer.