mailsrv145113.o-mx.dwightgrange.com has no NS records.
NS records for this zone are defined at dwightgrange.com.
NS records for this zone are defined at dwightgrange.com.
Question and response
Question
dig mailsrv145113.o-mx.dwightgrange.com. NS
Answer
The response has no answer records.
Authority
dwightgrange.com. 3601 SOA dns1.registrar-servers.com. hostmaster.registrar-servers.com. 1766566599 43200 3600 604800 3601
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0