mx.abuse.tucows.com has no NS records.
NS records for this zone are defined at tucows.com.
NS records for this zone are defined at tucows.com.
Question and response
Question
dig mx.abuse.tucows.com. NS
Answer
The response has no answer records.
Authority
tucows.com. 60 SOA ns1.tucows.com. hostmaster.tucows.com. 1771931751 1200 3600 2419200 60
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0