AutoSSL fails with "ERROR “domain.tld” is unmanaged"

Symptoms

AutoSSL fails with the following error, but the domain uses the local server for DNS management.

ERROR “domain.tld” is unmanaged. Verify this domain’s registration and authoritative
nameserver configuration to correct this problem.

Description 

The error occurs when the server doesn't manage the DNS for the domain, and AutoSSL cannot connect to the authoritative nameservers.

Workaround

Ensure that both TCP and UDP port 53 is open for inbound and outbound traffic through all security devices or firewalls.