Question: When I try to send a HTTP request like 

`GET /`
I can't reach to index.html or index.php. 
The host brings the page `/cgi-sys/defaultwebpage.cgi`.

When I try `GET /index.html`
This time i get a 404 not found error. It says `(none)/index.html` not found.

What could be the reason?

Answer: 
Looks like that `DocumentRoot` in the `httpd.conf` file is pointing to a different directory instead of where your `index.html` is.
I thought I had the same problem until looked at my page via anonymous access service (like [this](http://eu.amnotseen.com/)). Actually the problem was with my DNS cache.