Ethernet connected but no internet connection in Ubuntu 20.04

I have an ethernet connection. But I am getting no internet. I cannot visit any website or anything related to internet.

Here are some commands that I ran:

$ ping google.com
ping: google.com: Temporary failure in name resolution

$ sudo lshw -C network
  *-network
       description: Ethernet interface
       product: RTL810xE PCI Express Fast Ethernet controller
       vendor: Realtek Semiconductor Co., Ltd.
       physical id: 0
       bus info: pci@0000:02:00.0
       logical name: enp2s0
       version: 07
       serial: 10:7b:44:32:b5:91
       capacity: 100Mbit/s
       width: 64 bits
       clock: 33MHz
       capabilities: pm msi pciexpress msix vpd bus_master cap_list ethernet physical tp mii 10bt 10bt-fd 100bt 100bt-fd autonegotiation
       configuration: autonegotiation=on broadcast=yes driver=r8169 driverversion=5.11.0-41-generic firmware=rtl8106e-1_0.0.1 06/29/12 latency=0 link=no multicast=yes port=twisted pair
       resources: irq:16 ioport:e000(size=256) memory:ef000000-ef000fff memory:e0000000-e0003fff
  *-network:0
       description: Ethernet interface
       physical id: 1
       logical name: ipv6leakintrf0
       serial: 86:d4:7a:5b:33:1b
       capabilities: ethernet physical
       configuration: broadcast=yes driver=dummy driverversion=5.11.0-41-generic
  *-network:1
       description: Wireless interface
       physical id: 2
       bus info: usb@1:1
       logical name: wlx7cc2c61b3890
       serial: 7c:c2:c6:1b:38:90
       capabilities: ethernet physical wireless
       configuration: broadcast=yes driver=r8188eu driverversion=5.11.0-41-generic ip=192.168.31.85 multicast=yes wireless=IEEE 802.11bgn

$ ifconfig
enp2s0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 192.168.31.236  netmask 255.255.255.0  broadcast 192.168.31.255
        inet6 fe80::37e2:dfce:fe9a:3b87  prefixlen 64  scopeid 0x20<link>
        ether 10:7b:44:32:b5:91  txqueuelen 1000  (Ethernet)
        RX packets 4611  bytes 278152 (278.1 KB)
        RX errors 0  dropped 1  overruns 0  frame 0
        TX packets 126  bytes 16768 (16.7 KB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

ipv6leakintrf0: flags=195<UP,BROADCAST,RUNNING,NOARP>  mtu 1500
        inet6 fdeb:446c:912d:8da::  prefixlen 64  scopeid 0x0<global>
        inet6 fe80::e70e:7372:7fc3:14a7  prefixlen 64  scopeid 0x20<link>
        ether 72:39:c1:33:e1:52  txqueuelen 1000  (Ethernet)
        RX packets 0  bytes 0 (0.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 10953  bytes 1136027 (1.1 MB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

lo: flags=73<UP,LOOPBACK,RUNNING>  mtu 65536
        inet 127.0.0.1  netmask 255.0.0.0
        inet6 ::1  prefixlen 128  scopeid 0x10<host>
        loop  txqueuelen 1000  (Local Loopback)
        RX packets 31412  bytes 2334819 (2.3 MB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 31412  bytes 2334819 (2.3 MB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

$ ping -c3 8.8.8.8
PING 8.8.8.8 (8.8.8.8) 56(84) bytes of data.
64 bytes from 8.8.8.8: icmp_seq=1 ttl=58 time=294 ms
64 bytes from 8.8.8.8: icmp_seq=2 ttl=58 time=113 ms
64 bytes from 8.8.8.8: icmp_seq=3 ttl=58 time=137 ms

--- 8.8.8.8 ping statistics ---
3 packets transmitted, 3 received, 0% packet loss, time 2002ms
rtt min/avg/max/mdev = 113.372/181.329/293.792/80.097 ms

$ ls -al /etc/resolv.conf
lrwxrwxrwx 1 root root 39 Jul 14 00:58 /etc/resolv.conf -> ../run/systemd/resolve/stub-resolv.conf

$ cat /etc/resolv.conf
# This file is managed by man:systemd-resolved(8). Do not edit.
#
# This is a dynamic resolv.conf file for connecting local clients to the
# internal DNS stub resolver of systemd-resolved. This file lists all
# configured search domains.
#
# Run "resolvectl status" to see details about the uplink DNS servers
# currently in use.
#
# Third party programs must not access this file directly, but only through the
# symlink at /etc/resolv.conf. To manage man:resolv.conf(5) in a different way,
# replace this symlink by a static file or a different symlink.
#
# See man:systemd-resolved.service(8) for details about the supported modes of
# operation for /etc/resolv.conf.

nameserver 127.0.0.53
options edns0 trust-ad

$ ping -c3 www.google.com
ping: www.google.com: Temporary failure in name resolution

$ resolvectl status
Global
       LLMNR setting: no
MulticastDNS setting: no
  DNSOverTLS setting: no
      DNSSEC setting: no
    DNSSEC supported: no
          DNSSEC NTA: 10.in-addr.arpa
                      16.172.in-addr.arpa
                      168.192.in-addr.arpa
                      17.172.in-addr.arpa
                      18.172.in-addr.arpa
                      19.172.in-addr.arpa
                      20.172.in-addr.arpa
                      21.172.in-addr.arpa
                      22.172.in-addr.arpa
                      23.172.in-addr.arpa
                      24.172.in-addr.arpa
                      25.172.in-addr.arpa
                      26.172.in-addr.arpa
                      27.172.in-addr.arpa
                      28.172.in-addr.arpa
                      29.172.in-addr.arpa
                      30.172.in-addr.arpa
                      31.172.in-addr.arpa
                      corp
                      d.f.ip6.arpa
                      home
                      internal
                      intranet
                      lan
                      local
                      private
                      test

Link 4 (ipv6leakintrf0)
      Current Scopes: DNS
DefaultRoute setting: yes
       LLMNR setting: yes
MulticastDNS setting: no
  DNSOverTLS setting: no
      DNSSEC setting: no
    DNSSEC supported: no
  Current DNS Server: ::1
         DNS Servers: ::1
          DNS Domain: ~.

Link 3 (wlx7cc2c61b3890)
      Current Scopes: none
DefaultRoute setting: no
       LLMNR setting: yes
MulticastDNS setting: no
  DNSOverTLS setting: no
      DNSSEC setting: no
    DNSSEC supported: no

Link 2 (enp2s0)
      Current Scopes: none
DefaultRoute setting: no
       LLMNR setting: yes
MulticastDNS setting: no
lines 31-60
                      lan
                      local
                      private
                      test

Link 4 (ipv6leakintrf0)
      Current Scopes: DNS
DefaultRoute setting: yes
       LLMNR setting: yes
MulticastDNS setting: no
  DNSOverTLS setting: no
      DNSSEC setting: no
    DNSSEC supported: no
  Current DNS Server: ::1
         DNS Servers: ::1
          DNS Domain: ~.

Link 3 (wlx7cc2c61b3890)
      Current Scopes: none
DefaultRoute setting: no
       LLMNR setting: yes
MulticastDNS setting: no
  DNSOverTLS setting: no
      DNSSEC setting: no
    DNSSEC supported: no

Link 2 (enp2s0)
      Current Scopes: none
DefaultRoute setting: no
       LLMNR setting: yes
MulticastDNS setting: no
  DNSOverTLS setting: no
      DNSSEC setting: no
    DNSSEC supported: no

$ sudo service systemd-resolved status | grep Active
     Active: active (running) since Tue 2021-12-14 00:35:01 +06; 21h ago

What can I do? I have already tried mobile tethering and wifi is also connected. But that's also not working.

Update: The issue has been resolved once I uninstalled protonVPN. Just follow the instructions provided in the official protonVPN website to uninstall it and then follow the instruction in here.