System problem
Due to the damage of TCP/IP protocol or the loss of other network-related system files, the network connection may be disconnected or always in the state of obtaining IP, but you can still surf the Internet normally. However, if your cable is directly connected to the company's switch, the system cause can be ruled out.
Switch port problem
A switch failure will cause one or more ports to be unavailable, even if it looks normal on the physical connection. It is recommended that you try to change several ports for testing. If the problem persists after changing the port, it may be that the unit cable is bound to the IP of the core switch.
Router problem
If your line itself is bound to a port of the company switch, and this line has a fixed address, then no matter which computer you connect to, that computer will use this address. You can determine whether this is the case by connecting two computers separately and looking at the IP address. If the IP addresses are the same, you may need to buy a router or use a dual network card for soft routing. Buying a router is the simplest and most stable choice.