webpage cannot be accessed from other computer - apache

Question

I'm a newbie in httpd and my problem is I cannot access my webpage from other computer.
What I am trying to do is deploying with minimal httpd.conf file with following https://www.youtube.com/watch?v=1ZioHruINOA.
/etc/httpd/conf/httpd.conf is
Listen 0.0.0.0:80
User apache
Group apache
ServerName www.example.com
ErrorLog /var/log/httpd/error.log
LoadModule authz_host_module modules/mod_authz_host.so
LoadModule dir_module modules/mod_dir.so
DirectoryIndex index.html
DocumentRoot /var/www/html
<Directory /var/www/html>
AllowOverride None
Order allow,deny
allow from all
</Directory>
after I run command
sudo apachectl start
w3m 172.31.30.53
I can see the desired webpage(/var/www/html/index.html)
However, running command
w3m 172.31.30.53
on other computer's terminal does not work.
Thank you in advance.
edit1:
sudo ufw status
Status: active
To Action From
-- ------ ----
Apache Full ALLOW Anywhere
22 ALLOW Anywhere
80 ALLOW Anywhere
Anywhere ALLOW 0.0.0.0
Apache Full (v6) ALLOW Anywhere (v6)
22 (v6) ALLOW Anywhere (v6)
80 (v6) ALLOW Anywhere (v6)
edit2:
/etc/apache2$ nmap 127.0.0.1
Starting Nmap 6.40 ( http://nmap.org ) at 2018-05-20 21:31 UTC
Nmap scan report for localhost (127.0.0.1)
Host is up (0.00019s latency).
Not shown: 998 closed ports
PORT STATE SERVICE
22/tcp open ssh
80/tcp open http
Nmap done: 1 IP address (1 host up) scanned in 0.91 seconds

Answer 1

Sounds to me that you are trying to run your webserver on a Linux machine. If you want to access your webpages from other computers, you might want to check your firewall settings. Accessing locally should work, but depending on your distro, you'll have to allow access. On Ubuntu you'll have to check ufw.
EDIT 1:
Try nmap from another machine. This way you can see what ports are available. Example: nmap yourmachine