If your active QR Codes are not functioning properly, it is likely due to design issues. Some reader applications and phone cameras may have difficulty scanning complicated QR Codes.
Here are some essential design considerations:
Ensure that there is a significant contrast between the QR Code's background and foreground. The foreground should be darker than the background. (e.g. a black QR Code on a white background may not be scannable by all readers).
Make sure the QR Code's size is appropriate for the scanning distance. (Dynamic QR Codes should generally be no smaller than 2 x 2 cm (.8 x .8 in), and Static QR Codes should generally be no smaller than 3 x 3 cm (1.2 x 1.2 in)).
If you're using a logo, ensure that it doesn't obstruct important elements of the QR Code.
It's also a good idea to sign in to your account to verify that there isn't a problem with your subscription.