1. When I am under health observation, the health code will show places I have not been to. In this case, you can wait patiently. 2. My information is used or stolen by others, and other people's related behaviors will cause my health code to show places I have not been to. In this case, you can appeal to the big data center. 3. The big data system may also have errors in capturing information, causing places that have not been visited. I can give feedback through "I want to appeal" and the city's big data center will handle it as soon as possible.