1. Incorrect IP address and DNS settings: You can try to modify the IP address to get it automatically. When some users input the IP address, if they click OK without completing the input, the IP address will be wrong, resulting in the inability to access the Internet.

2. Network setting problem: the mobile phone network is set incorrectly, and the campus network cannot be connected. You can check the WiFi settings in your phone to make sure that you have selected the correct WiFi network and entered the correct password.