No network connection on Kubuntu Plasma Desktop

sudo dhclient

ping 8.8.8.8

ip link

nmcli

nmcli dev status

sudo apt install plasma-nm

sudo apt install network-manager

sudo nano /etc/NetworkManager/NetworkManager.conf // didn't work out

[main]
plugins=ifupdown,keyfile

[ifupdown]
managed=false

[device]
wifi.scan-rand-mac-address=no

change the line managed=false to managed=true // no effect

Add following:

[keyfile]

unmanaged-devices=none; OR for multiple devices

unmanaged-devices=none;your-device-name; // device name => ls /sys/class/net || ip link || nmcli

sudo service network-manager restart // didn't work

sudo systemctl restart NetworkManager

Failed to restart network-manager.service: Unit network-manager.service not found.

sudo apt reinstall network-manager

systemctl status NetworkManager

nmcli dev show // make sure device is managed

Reset Network Device Configuration:

sudo ifconfig device-name 0.0.0.0 down // didn't work

sudo ip addr flush dev device-name // didn't work

/etc/network/interfaces && /etc/sysconfig/network-scripts/ // Network Configuration Files

nmcli con show // list all existing NetworkManager connections names

nmcli con mod "Wired connection 1" ipv4.addresses ''
nmcli con mod "Wired connection 1" ipv4.gateway ''
nmcli con mod "Wired connection 1" ipv4.dns ''

nmcli con show 'Wired connection 1'

sudo systemctl restart NetworkManager

nmcli dev show  // look for state change

BEFORE => GENERAL.STATE:                          10 (unmanaged)

NOW => GENERAL.STATE:                          100 (connected (externally))

SOLVED! => NM works and connection is UP from the start