I have corrected the FQDN error by adding
jeroen@jeroen-desktop:/etc/apache2$ apache2 -k restart
apache2: Could not reliably determine the server's fully qualified domain name, using 127.0.1.1 for ServerName
httpd not running, trying to start
(13)Permission denied: make_sock: could not bind to address 0.0.0.0:80
no listening sockets available, shutting down
Unable to open logs
Also, Apache starts as root and changes to the defined apache user; apachectl needs to be executed as root. If you shell into a remote server as root, you don't need sudo. On your local machine, you probably aren't root and need sudo or su.