Why doesn't it recognize the Ethernet connection?

Question

Computer networks

There is a modem. I want to connect with an ethernet connection, but it ends up saying "unidentified network" on my computer.
There is a second computer, it is connected via Ethernet to the same modem. The network is working. When I connect the same cable - it works for me too.
BUT doesn't work when I plug in my cable. Why? How to setup? Possible reasons?
p.s. The cables are the same, without mechanical damage.

Answer 1

Whether DHCP is issued not on a poppy?

Answer 2

Throw out the patch cord, install a new one, or re-compress.