mx.teseonline.com has no NS records.
NS records for this zone are defined at teseonline.com.
NS records for this zone are defined at teseonline.com.
Question and response
Question
dig mx.teseonline.com. NS
Answer
The response has no answer records.
Authority
teseonline.com. 3600 SOA dns.teseonline.com. hostmaster.teseonline.com. 1923555679 43200 3600 604800 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0