Address error, network error. When using the call interface of the perfect campus, you need to use the correct address and good network signal. If the calling interface fails due to an address error or a network error, the service interface call is unsuccessful. Need to find maintenance personnel to change the address at the maintenance point, and reconnect at the place with good network signal. Calling an interface refers to a form of constraint, or a connection path, which provides general processing services for unrelated classes.