Address already in use: AH00072: make_sock: could not bind to address [::]:80

Question

I have modified some settings in /etc/apache2/sites-enabled/000-default.conf and now I can't start Apache. What's the reason and how can I fix this?

ubuntu@ip:~$ sudo /etc/init.d/apache2 stop
 * Stopping web server apache2                                                                                                       *
ubuntu@ip:~$ sudo /etc/init.d/apache2 start
 * Starting web server apache2                                                                                                      (98)Address already in use: AH00072: make_sock: could not bind to address [::]:80
(98)Address already in use: AH00072: make_sock: could not bind to address 0.0.0.0:80
no listening sockets available, shutting down
AH00015: Unable to open logs
Action 'start' failed.
The Apache error log may have more information.