mx.surtsports.com has no NS records.
NS records for this zone are defined at surtsports.com.
NS records for this zone are defined at surtsports.com.
Question and response
Question
dig mx.surtsports.com. NS
Answer
The response has no answer records.
Authority
surtsports.com. 3600 SOA dns.surtsports.com. hostmaster.surtsports.com. 1491370670 43200 3600 604800 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0