It seems like your web server is not running on your server. You can check the same by executing the appropriate command as follows:
For Apache/Apache2 web server:
service httpd status
For Nginx web server:
service nginx status
For Lighttpd web server:
service lighttpd status
Also in order to check if port 80 is open or close you can check it here:
http://ping.eu/port-chk/
Let us know the output of the command as per the web server you are using on your server.