htaccess do not work for subdomain in codeigniter

Code:
<IfModule mod_rewrite.c>

    RewriteEngine On

    RewriteBase /

  



    RewriteCond %{REQUEST_URI} ^system.*

    RewriteRule ^(.*)$ /index.php?/$1 [L]





    RewriteCond %{REQUEST_URI} ^application.*

    RewriteRule ^(.*)$ /index.php?/$1 [L]

    RewriteCond %{REQUEST_FILENAME} !-f

    RewriteCond %{REQUEST_FILENAME} !-d

    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.

    # Submitted by: ElliotHaughin



    ErrorDocument 404 /index.php

</IfModule>