1. Network setting problem: The mobile phone network is set incorrectly, which will make it impossible to connect to the campus network. You need to check the WiFi settings in your phone to make sure that you have selected the correct WiFi network and entered the correct password. You can try to forget the saved WiFi network and re-enter the password connection.
2. Signal problem: The signal of campus network is influenced by many factors, such as buildings and other radio equipment. If the signal is weak or there are interference sources, it will lead to the inability to connect to the campus network. You can try to move to another location with good signal, or use other equipment for testing.