Computer Tips - Unable to find a virtual host listening on port 80 which is currently needed for Certbot to prove to the CA that you control your domain. Please add a virtual host for port 80.

Date: 2019jan21 Q. Unable to find a virtual host listening on port 80 which is currently needed for Certbot to prove to the CA that you control your domain. Please add a virtual host for port 80. A. I didn't have a VirtualHost in my Apache configuration because it was real (not virtual) ie the only webserver on this machine. In order to make Certbot work I added:
<VirtualHost example.com:80> ServerName example.com </VirtualHost>
In /etc/httpd/conf.d/example_com.conf Re-running Certbot then worked.