Sometimes, the DNS records can be set incorrectly (sometimes through migration from another host, and sometimes just human error!).
It is possible to entirely reset the DNS zone so that the domain has all records set back to the 'default' records provided by cPanel.
To do this, go to cPanel -> Domains -> Zone Editor
From here, select 'Manage' against the domain...
Next, click 'Actions', then 'Reset DNS Zone'...
Connect to your server via SSH
SSH allows secure file transfer and remote logins over the internet. Your connection via SSH is...