1. Application package interception: When the system detects that the application package violates its developer's terms or contains harmful content, it will automatically intercept network signals.
2. The certificate has expired: the signing certificate is valid for one year or less. If you continue to use this certificate to sign the application package after the certificate expires, you will not be able to connect to the network normally.
3. Network environment problem: there is a problem with the network connected to the router or the network connected to the device is in a weak signal state.