mx2.myottmail.com has no NS records.
NS records for this zone are defined at myottmail.com.
NS records for this zone are defined at myottmail.com.
Question and response
Question
dig mx2.myottmail.com. NS
Answer
The response has no answer records.
Authority
myottmail.com. 600 SOA pdns05.domaincontrol.com. dns.midmaine.com. 2019100402 28800 7200 604800 600
Additional
. 0 OPT ; payload 1280, xrcode 0, version 0, flags 0