The following article shows how to settle a hostname mistake in cPanel. This error implies that a hostname record was not included for the server name. To settle this, you should contact support and demand a hostname record be included for your VPS.
As an option, you can refresh the hostname of the VPS to a completely qualified domain name.
To update the hostname to a qualified domain name:
1. Open a web program and interface with your cPanel Control Panel situated at https://ip address:2087.
2. Log in as the Administrator utilizing the data sent to you in your setup email.
3. From the menu, under Networking Setup, click Hostname.
4. Enter a completely qualified domain name as the new Hostname and click Change.