If the DNS entries for your hostname are not set up correctly, you may get a message saying something similar to this:
IMPORTANT: Do not ignore this email.
The hostname (server.domain.com) resolves to
xx.xx.xx.xx. It should resolve to zz.zz.zz.zz. Please be sure
that the contents of /etc/hosts are configured correctly, and also
that there is a correct 'A' entry for the domain in the zone file.
Some or all of these problems can be caused by /etc/resolv.conf
being setup incorrectly. Please check that file if you believe
everything else is correct.
You may be able to automatically correct this problem by using the
'Add an A entry for your hostname' option under 'DNS Functions' in
your Web Host Manager.
Follow the instructions that cPanel has provided by checking to see if you can solve this issue using WHM tools. Login to your server's WHM (not cPanel) by going to https://[server_IP_address]:2087 in your web browser. From there locate DNS Functions -> Click on 'Add an A entry for your hostname' -> Click on the 'Add entry' button if the displayed information looks correct.
Here there is a video tutorial regarding adding an A entry for your hostname:
If the error is not yet resolved make sure that /etc/hosts is configured correctly.
Login through SSH and this is how your /etc/hosts file should look like (x.x.x.x should be the main IP server address):
root@server [~]# cat /etc/hosts
127.0.0.1 localhost
x.x.x.x server.domain.com server
This issue can also be caused by /etc/resolv.conf being setup incorrectly.
Please check that file if you believe everything else is correct.