I use VMWare Workstation with Ubuntu Server. My domain name akerka.com parked on its IP and worked property (I see an Apache’s greeting page). I try to set up Nextcloud. But when I request a certificate I get following errors:
Domain: akerka.com
Type: unknownHost
Detail: No valid IP addresses found for akerka.com
The IP address for your domain isn’t a public IP address, but a private one:
akerka.com. 600 IN A 192.168.1.17
Let’s Encrypt needs a publically accessible IP address for http-01 authentication. As an alternative, you might choose to use the dns-01 challenge if a public IP address isn’t available.