The health code cannot be used. First of all, it may be caused by the mobile phone network. This may happen if the mobile phone has a poor network speed or no network connection. Users are advised to check the network connection status of the mobile phone, or disconnect the mobile phone network and then try to reconnect, which will generally solve the problem.
Guan Wei's "WeChat small method" builds a healthy Wuhan, and the card-free hospital further helps.