mx.nicolecooperbooks.com has no NS records.
NS records for this zone are defined at nicolecooperbooks.com.
NS records for this zone are defined at nicolecooperbooks.com.
Question and response
Question
dig mx.nicolecooperbooks.com. NS
Answer
The response has no answer records.
Authority
nicolecooperbooks.com. 3600 SOA dns.nicolecooperbooks.com. hostmaster.nicolecooperbooks.com. 1814703143 43200 3600 604800 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0