ng to gov.ng: An SOA RR with owner name (gov.ng) not matching the zone name (ng) was returned with the NODATA response. See RFC 1034, Sec. 4.3.4, RFC 2308, Sec. 2.2. (194.0.1.29, 2001:678:4::1d, UDP_-_EDNS0_4096_D_KN)
gov.ng/DS has errors; select the "Denial of existence" DNSSEC option to see them.