Why scans fail
1. The screen is too dim
Auto-brightness dims the display when the phone is out of direct light, which is exactly where it ends up when you hand it over. Scanners need contrast, and a dim screen gives them almost none. Turn brightness to maximum manually before you queue, and turn off auto-brightness for the duration.
2. Glare and screen protectors
A matte screen protector scatters the light from the scanner’s illumination LED, turning the crisp edges of the code into a grey blur. A cracked protector is worse — each crack becomes a line the scanner tries to read. Remove the case or switch to a phone without a protector if you can.
3. The code is cropped
Every 2D barcode needs a "quiet zone" — empty margin around the symbol. Four modules wide is the minimum for QR, two for Data Matrix. Zooming in until the code fills the screen edges removes the quiet zone and stops most scanners from locking on. Keep some empty space around the code.
4. Wrong distance or angle
Consumer scanners focus best at 10–20 cm. Too close and the camera cannot focus; too far and the code is too small to decode. Hold the phone flat, not at an angle — scanners can handle rotation, but perspective distortion is harder.
5. The wrong copy of the code
For rotating codes, a screenshot taken yesterday is a screenshot of an expired ticket. The scanner reads a perfectly valid barcode, but the system rejects it because the time window has passed. Open the issuer’s app or wallet pass live.
A 30-second checklist before you reach the gate
- Brightness slider all the way up.
- Auto-brightness off.
- Rotation lock on, phone upright.
- Ticket open — not in your email inbox, not buried under a notification.
- If it is an app-generated code, give it a few seconds to refresh.
- Wipe the screen once with a sleeve or cloth.
If it still will not scan
Every ticket carries the ID in human-readable form, usually directly below the barcode. Staff can type this in by hand, which takes ten seconds and always works. If the scanner keeps beeping red, offer the human-readable code out loud.
If the ID itself is rejected — not the scan, the ticket — the issue is in the issuer’s system, not your phone. Step out of the queue and email the issuer from your confirmation. We cannot help with individual tickets; the issuer can.