1. See if WeChat has permission to call the camera.

2. Whether the cell phone network signal is normal.

3. Whether the camera function is normal.

4. Whether it is occupied by other software.

5. Adjust the position of mobile phone and QR code. Mask two-dimensional code, namely mask self-adhesive two-dimensional code anti-counterfeiting label, is a kind of anti-counterfeiting label developed on the basis of self-adhesive label, also known as self-adhesive anti-counterfeiting label. The paper of self-adhesive label is imported materials, such as surface packaging and printing, embedding anti-counterfeiting label expertise, spraying anti-counterfeiting code, scraping layer, laminating layer, front end, film cutting and so on.