mx0102.titan.email has no NS records.
NS records for this zone are defined at titan.email.
NS records for this zone are defined at titan.email.
Question and response
Question
dig mx0102.titan.email. NS
Answer
The response has no answer records.
Authority
titan.email. 900 SOA ns-451.awsdns-56.com. awsdns-hostmaster.amazon.com. 1 7200 900 1209600 86400
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0