When setting up different FTP, mail and MySQL programs, you need to specify the server hostname.
You can check what server your account is hosted on in different ways.
One of them is to log into cPanel by typing into a browser http://yourdomain.com/cpanel:
You will be redirected to the cPanel login page with the hostname in the link:
In this example, the hostname is server126.web-hosting.com
Or you can look up the hostname in Hosting Welcome Guide > Package Information section:
or you can just use the command whois on the terminal as you will see