Removing index.php in CodeIgniter resulting 5xx server error

RewriteEngine on
RewriteCond $1 !^(index\.php|images|robots\.txt|css)
RewriteRule ^(.*)$ ./index.php/$1 [L]

I think i might have solved it using this configuration:

my .htaccess file:

<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /myfolder

#Removes access to the system folder by users.
#Additionally this will allow you to create a System.php controller,
#previously this would not have been possible.
#'system' can be replaced if you have renamed your system folder.
RewriteCond %{REQUEST_URI} ^system.*
RewriteRule ^(.*)$ /index.php/$1 [L]

#When your application folder isn't in the system folder
#This snippet prevents user access to the application folder
#Submitted by: Fabdrol
#Rename 'application' to your applications folder name.
RewriteCond %{REQUEST_URI} ^application.*
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,QSA]
</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>

My config.php file:

$config['index_page'] = '';
$config['uri_protocol'] = 'AUTO';

It turns out that since my application (my ci_root) is not in my root (public_html) i need to amend the RewriteBase from "/" to "/path_to_your_application"

And it turns out if you are creating a subdomain called "subdomain" it will create a folder inside your public_html named "subdomain" and you should treat this as the root of your subdomain. Hence i set my RewriteBase to "/myfolder" instead of "/my_subdomain_folder/myfolder".

I hope this solution could help others.

Thanks all for the helps and hints.

Just add a ? after index.php

RewriteEngine On
RewriteBase /
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond $1 !^(index\.php|robots\.txt|humans\.txt|license\.txt|sitemap\.xml|assets)
RewriteRule ^(.*)$ index.php?/$1 [L]

I also recomend to let view the files but not the directories with:

Options -Indexes