[root@centOS ~]# systemctl start network.service
Restarting network (via systemctl): Job for network.service failed because the control process exited with error code.
See “systemctl status network.service” and “journalctl -xe” for details.
[root@centOS ~]# systemctl status network.service

[root@centOS ~]# journalctl -xe[root@centOS ~]# systemctl start network.service
Restarting network (via systemctl): Job for network.service failed because the control process exited with error code.
See “systemctl status network.service” and “journalctl -xe” for details.
[root@centOS ~]# systemctl status network.service
[root@centOS ~]# journalctl -xe

Reason.
On CentOS system, there are currently two network management tools, NetworkManager and network. If both are configured, it will cause conflicts, and NetworkManager will clean up the routes when the network is disconnected. If some custom routes, which are not added to NetworkManager’s configuration file, the routes are cleaned up and need to be custom added on after the network is connected.
Solution.
1. Stop the networkmanager service
systemctl stop NetworkManager
systemctl disable NetworkManager
2. restart the network card, it is OK
systemctl restart network
systemctl status network