When your device will not scan a QR code on a centers kiosk, it is likely an issue with the device itself. To be sure, have any staff member at the center see if they can scan it as well with another device such as their phone or a class tablet. If it will bring up the kiosk on any other device, it would be some sort of issue with you device.

In that case, here are a few reason your device may not be scanning a QR code and how to troubleshoot them:

Your phone is not using updated software:

If you are using an Apple device you will need software version 11 or higher installed. Andriod devices will need software version 9 or higher. If it is still something software related, you can try and grab an app from an app store that may help your phone read QR devices

The angle might be off or there could be distance issue

You will want to ensure that your phone is not tilted at any type of angle in order to read a QR device. Make sure the phone is level with the face of the kiosk when attempting to scan the QR code. 

You may also be holding the phone either too close or too far away to read the QR code. If the phone is level, try moving your phone further out or closer in to see if your scanner will then pick it up.

Your camera lens may be dirty

If your camera lens is dirty or has any type of smudge on it, it may prevent your device from scanning the QR code. Clean your camera area on your phone and see if it allows you to then scan the QR code.

Your screen brightness is too low

Your screen brightness does play into your phones ability to read a QR code. If you are trying to scan a QR code with a low screen brightness, it may prevent your phone from registering it. Try increasing your phone brightness from its settings and see if that helps it register the QR code.