CodeIgniter Error 404 on root domain using PHP CGI - php

Question

So, today I upgrade PHP and apache on my server to version PHP 5.4 and Apache 2.4.
And then I noticed on one domain using older version of codeigniter (I've try to echo CI_VERSION but it shows nothing) is showing error 404 on the root domain. But typing domain.com/home works fine. (home is my default controller). Typing any other controller also working fine. But domain.com shown error 404.
.htaccess
<IfModule mod_rewrite.c>
Options +FollowSymLinks
RewriteEngine On
RewriteBase /
#'system' can be replaced if you have renamed your system folder.
RewriteCond %{REQUEST_URI} ^system.*
RewriteRule ^(.*)$ index.php/$1 [L]
#Checks to see if the user is attempting to access a valid file,
#such as an image or css document, if this isn't true it sends the
#request to index.php
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^(.*)$ index.php/$1 [L]
#This last condition enables access to the images and css folders, and the robots.txt file
RewriteCond $1 !^(index\.php|apc\.php|assets|nivo-slider|hr|stm|elearning|docs|adminer|favicon\.ico|file|flash|tinymce|robots\.txt)
RewriteRule ^(.*)$ index.php/$1 [L]
</IfModule>
<IfModule !mod_rewrite.c>
# If we don't have mod_rewrite installed, all 404's
# can be sent to index.php, and everything works as normal.
ErrorDocument 404 /application/errors/404.php
</IfModule>
config.php
$config['base_url'] = "http://".$_SERVER['HTTP_HOST'];
$config['index_page'] = "";
$config['uri_protocol'] = "AUTO";
routes.php
$route["default_controller"] = "home";
$route["error_controller"] = "error";
$route['scaffolding_trigger'] = "";
I've trying change uri_protocol to QUERY_STRING & REQUEST_URI but still not working.

Answer 1

I managed to solve this problem by adding DirectoryIndex home on my .htaccess.