Hosts file

/etc/hosts

Edit your hosts file and make sure it looks similar to this:

127.0.0.1    localhost server.your-domain.com
::1               localhost localhost.localdomain localhost6 localhost6.localdomain6
127.0.1.1    your-domain.com
127.0.1.1    server.your-domain.com server
127.0.1.1    www.your-domain.com www

Replace your-domain.com with your servers domain. You can also add some more domains e.g.

127.0.1.1    cloud.your-domain.com cloud

and so on.