1. Network problem: Tencent's QR code application needs to be connected to the network. If the network is unstable or has problems, the application may fail.
2. Application process: The application process of QR code is complicated, and improper operation or minor mistakes may also lead to application failure.
3. System problems: When using Tencent questionnaire, there may be system problems, including server problems and software version problems, which may also lead to the failure of QR code application.
If you can't complete the QR code application of Tencent questionnaire, you can try to operate again to ensure the normal network connection, or contact Tencent questionnaire customer service department for help.