Restart apache when it will report an error:
apache2: Could not Reliably the Determine at The Server's Domain name Fully qualified, a using the Set at The 127.0.1.1 'ServerName' the this Directive Globally the Message to the suppress value.
Solution:
generate a file fqdn.conf
vim /etc/apache2/conf-available/fqdn.conf
ServerName localhost write
and tell apache to use
a2enconf fqdn
Restart apache2, the problem is solved
service apache2 restart
