Connection enp6s0 is not available on the device enp6s0 at this time

edit

I have a problem with connecting to ethernet, Wifi works ok. My OS is Fedora 4.20.14-200.fc29.x86_64. Cable is connected on the back of the PC. But on Network settings its shown as Cable unplugged next to a slider. The slider is greyed and cannot be moved. Its configured to IPv4 Automatic.

nmcli con show

enp6s0 6bc1cca4-0dc5-4be7-9b3f-2ac46c16e520 ethernet --
Office 4a3d6532-e8f2-40fb-b227-efdd9dd6ee3f ethernet --

nmcli dev status

DEVICE TYPE STATE CONNECTION
enp0s31f6 ethernet unavailable --
enp6s0 ethernet unavailable --

ifconfig

enp0s31f6: flags=4099<up,broadcast,multicast> mtu 1500
ether e0:d5:5e:69:fc:35 txqueuelen 1000 (Ethernet)
RX packets 0 bytes 0 (0.0 B)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 0 bytes 0 (0.0 B)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
device interrupt 16 memory 0xf7300000-f7320000

enp6s0: flags=4099<up,broadcast,multicast> mtu 1500
ether e0:d5:5e:69:fc:33 txqueuelen 1000 (Ethernet)
RX packets 0 bytes 0 (0.0 B)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 0 bytes 0 (0.0 B)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
device memory 0xf7200000-f721ffff

ifcfg-enp6s0 looks like:

HWADDR=E0:D5:5E:69:FC:33
TYPE=Ethernet
PROXY_METHOD=none
BROWSER_ONLY=no
BOOTPROTO=dhcp
DEFROUTE=yes
IPV4_FAILURE_FATAL=no
IPV6INIT=no
IPV6_AUTOCONF=yes
IPV6_DEFROUTE=yes
IPV6_FAILURE_FATAL=no
IPV6_ADDR_GEN_MODE=stable-privacy
NAME=enp6s0
UUID=6bc1cca4-0dc5-4be7-9b3f-2ac46c16e520

and ifcfg-Office:

HWADDR=E0:D5:5E:69:FC:35
TYPE=Ethernet
PROXY_METHOD=none
BROWSER_ONLY=no
BOOTPROTO=none
IPADDR=10.0.0.2
PREFIX=24
GATEWAY=10.0.0.1
DNS1=8.8.8.8
DEFROUTE=yes
IPV4_FAILURE_FATAL=no
IPV6INIT=yes
IPV6_AUTOCONF=yes
IPV6_DEFROUTE=yes
IPV6_FAILURE_FATAL=no
IPV6_ADDR_GEN_MODE=stable-privacy
NAME=Office
UUID=4a3d6532-e8f2-40fb-b227-efdd9dd6ee3f
ONBOOT=yes

IP addresses are made up here.

ifup enp6s0

Error: Connection activation failed: No suitable device found for this connection.

nmcli con up enp6s0

Error: Connection activation failed: No suitable device found for this connection

nmcli dev con enp6s0

Error: Failed to add/activate new connection: Connection 'enp6s0' is not available on the device enp6s0 at this time.

Please, help!