Hello, codeigniter based cms gets 500 internal server error on my newly installed host. Mod rewrite c is activated. What to do? 
Try uploading a test HTML or PHP file and access it via your browser to determine if the issue is with the application you are using or if it's isolated to the account. If the issue persists, try temporarily disabling your .htaccess file to rule out any invalid rewrite rules.If I upload same files to other hosting provider, everything's ok, and I don't know what's the reason of that. It seems codeigniter has some problems
AddDefaultCharset UTF-8
RewriteEngine On
Options -Indexes
RewriteCond %{REQUEST_URI} ^system.*
RewriteRule ^(.*)$ /index.php?/$1 [NC,L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_URI} !^(/index\.php|/resources|/robots\.txt|/favicon\.ico|/templates)
RewriteRule ^(.*)$ /index.php?/$1 [L,QSA]