Sudo appears unable to resolve host Solution

In the Ubuntu environment, assume that this machine is named ABC (the hostname of the machine). This warning message is displayed every time you run sudo:
Sudo: Unable to Resolve Host ABC
Although sudo can still be executed normally, the warning message is sent out every time, and this is only a problem in the anti-solution of the machine, so it is set directly from/etc/hosts to make ABC (hostname) you can return the IP address of 127.0.0.1.

Original/etc/hosts content

127.0.0.1 localhost

# The following lines are desirable for IPv6 capable hosts

: 1 localhost ip6-localhost ip6-loopback ip6-loopback

Fe00: 0 ip6-localnet
Ip6-mcastprefix ff00: 0
Ff02: 1 ip6-allnodes
Ff02: 2 ip6-allrouters

Ff02: 3 ip6-allhosts

Add the Host Name (hostname) after 127.0.0.1 localhost, and change the/etc/hosts content to the following:

127.0.0.1 localhost ABC # Make sure the name is consistent with the host name in/etc/hostname.
# Or change to the following two rows
#127.0.0.1 localhost

#127.0.0.1 ABC

After the settings are complete, there will be no more prompts when using sudo.