networking – Ethernet link is down

My Ubuntu 20.04 laptop can connect through wireless but not wired. ip link shows:

1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
2: enp0s31f6: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc fq_codel state DOWN mode DEFAULT group default qlen 1000
    link/ether 70:5a:0f:d8:0a:f7 brd ff:ff:ff:ff:ff:ff
3: wlp2s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP mode DORMANT group default qlen 1000
    link/ether 44:85:00:b5:6d:82 brd ff:ff:ff:ff:ff:ff

I tried sudo ip link set up dev enp0s31f6 but the link remained down.

lspci -nnk | grep 0200 -A3 gives:

00:1f.6 Ethernet controller (0200): Intel Corporation Ethernet Connection I219-V      (8086:1570) (rev 21)
    Subsystem: Hewlett-Packard Company Ethernet Connection I219-V (103c:8079)
    Kernel driver in use: e1000e
    Kernel modules: e1000e

dmesg|grep e1000e gives:

(    4.095621) e1000e: Intel(R) PRO/1000 Network Driver - 3.2.6-k
(    4.095622) e1000e: Copyright(c) 1999 - 2015 Intel Corporation.
(    4.095640) e1000e 0000:00:1f.6: enabling device (0000 -> 0002)
(    4.096716) e1000e 0000:00:1f.6: Interrupt Throttling Rate (ints/sec) set to dynamic conservative mode
(    4.339134) e1000e 0000:00:1f.6 0000:00:1f.6 (uninitialized): registered PHC clock
(    4.411453) e1000e 0000:00:1f.6 eth0: (PCI Express:2.5GT/s:Width x1) 70:5a:0f:d8:0a:f7
(    4.411455) e1000e 0000:00:1f.6 eth0: Intel(R) PRO/1000 Network Connection
(    4.411521) e1000e 0000:00:1f.6 eth0: MAC: 12, PHY: 12, PBA No: FFFFFF-0FF
(    4.429803) e1000e 0000:00:1f.6 enp0s31f6: renamed from eth0
( 2049.084704) e1000e: enp0s31f6 NIC Link is Down

What is a possible solution?