How to break the LAN of Yancheng Institute of Technology

I graduated from a salt worker this year, and I still have this bag in my mobile phone. I used 1 for many years before. When I disconnect this network, I just close it or unplug the network cable, or I can close the page. At that time, I just turned off my phone or just unplugged the network cable. Seriously, this network really didn't work. Every time, it is only after the power failure that the mobile network is connected.