mx.krivanto.com has no NS records.
NS records for this zone are defined at krivanto.com.
NS records for this zone are defined at krivanto.com.
Question and response
Question
dig mx.krivanto.com. NS
Answer
The response has no answer records.
Authority
krivanto.com. 3600 SOA dns.krivanto.com. hostmaster.krivanto.com. 1569045310 43200 3600 604800 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0