Check whether the crystal head is broken or the network port is broken. If the crystal head is broken, press one or change a network cable;If the network port is broken, I suggest you buy a built-in network card. The maintenance cost is not cheap, and there are many sequelae.
The network card is integrated on the mainboard and must be replaced at the maintenance station. If it is inconvenient, you can buy a wired network card and a wireless network card with USB interface to use!