The SOA record for the zone is required to be present in the primary Name Server and is not found. This usually means that the zone file is not setup properly in the primary Name Server host. It may also be due to any of the following reasons.
The Name Server domain is actually not running at all. Start your Name Server domain before running this test again.
The Name Server domain is not reachable from the Internet because there is a firewall or filtering router that is blocking connections to port 53 on this host for both UDP and TCP connections. The firewall configuration must permit connections on this port from any host on the Internet for the DNS to function properly.