The health code could not be scanned for the following reasons:
1. The current user's network is very poor. Users are advised to check the network status of their mobile phones.
2. Only when the current health code is invalid will the results not be scanned. If the health code is invalid, the user can refresh it again.
3. The current system is out of order, so users are advised to wait for some time before re-operating. Due to the epidemic, people need to scan the health code to locate everyone's location.