You can find below error on /var/log/message/
Issue::
NetworkManager[642]: <info> Activation (enp0s3) successful, device activated.
avahi-daemon[531]: Registering new address record for fe80::a00:27ff:fe6a:55a4 on enp0s3.*.
qidiziCentos kernel: e1000: enp0s3 NIC Link is Down
NetworkManager[642]: <info> (enp0s3): link disconnected (deferring action for 4 seconds)
NetworkManager[642]: <info> (enp0s3): link disconnected (calling deferred action)
NetworkManager[642]: <info> (enp0s3): device state change: activated -> unavailable (re
fix ::
$ systemctl restart networkmanager
$ systemctl restart network
$ ifdown <devicename, e.g. enp0s8>
$ ifup <devicename, e.g. enp0s8>
