mx.tors.info has no NS records.
NS records for this zone are defined at tors.info.
NS records for this zone are defined at tors.info.
Question and response
Question
dig mx.tors.info. NS
Answer
The response has no answer records.
Authority
tors.info. 3600 SOA dns.tors.info. hostmaster.tors.info. 1555264403 43200 3600 604800 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0