What to do if the sudo command gives an error in Lubuntu Ubuntu Linux?

Question

ubuntu

When I try to type the command sudo nautilus in the Linux Ubuntu terminal with the lubuntu environment (hereinafter simply Lubuntu), I get an error:
sudo: error in /etc/sudo.conf, line 0 while loading plugin "sudoers_policy"
sudo: /usr/lib/sudo/sudoers .so must be only be writable by owner
sudo: fatal error, unable to load plugins
The same error comes up when trying to enter the command sudo -i or sudo su! Reboot doesn't help! The system cannot be used! What to do???!!!

Answer 1

Boot from any Linux boot disk/flash drive, mount your Linux partition and change the permissions on the /usr/lib/sudo/sudoers.so file so that only root can be written to it?

Answer 2

First two google links:
Solution one
Solution two
You can also use su if you have no problems with it.

Linux Ubuntu with lubuntu environment

There is no such environment. The distribution is called Lubuntu , and the environment is LXQT .