sudo: unable to resolve host {hostname}: Temporary failure in name resolution

Recently, I tried to run the command, sudo apt-get update and got the Temporary failure in name resolution error. But, after that the command proceeded and went on to update. Should I worried about the error. Below is the complete log:

sudo apt-get update
sudo: unable to resolve host {hostname}: Temporary failure in name resolution
Hit:1 http://in.archive.ubuntu.com/ubuntu focal InRelease                                                                                                                                                 
Get:2 http://in.archive.ubuntu.com/ubuntu focal-updates InRelease [114 kB]                                                                                                                                
Get:3 http://security.ubuntu.com/ubuntu focal-security InRelease [114 kB]                                                                                                                                 
Fetched 6,581 kB in 6s (1,180 kB/s)                                       
Reading package lists... Done
 

It seems likely that your computer's hostname is not configured correctly. There are two files you should check; /etc/hostname contains just your computer's name, and /etc/hosts will have a line that maps the IP address 127.0.1.1 to your hostname. For example, those files might look like:

username@ubuntu ~ $ cat /etc/hostname
ubuntu

username@ubuntu ~ $ cat /etc/hosts
127.0.0.1       localhost
127.0.1.1       ubuntu

# The following lines are desirable for IPv6 capable hosts
::1     ip6-localhost ip6-loopback
fe00::0 ip6-localnet
ff00::0 ip6-mcastprefix
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters

If you don't have those, try adding them -- keep in mind that a hostname should only consist of letters, numbers, and hyphens -- then reboot and see if you have that error again.