1. Scanning equipment problem: Make sure that the equipment used (such as mobile phone or tablet computer) has the function of scanning QR code, and the camera is clean, free from dirt and damage.

2. Network problem: The device is not connected to the network, or the network connection is unstable, which will also cause the scanning function to fail to work normally.

3. Software problem: If the App of the Electronic Taxation Bureau fails, or the App is not updated in time, the scanning function will not work normally.