mx1.smtp190.com has no NS records.
NS records for this zone are defined at smtp190.com.
NS records for this zone are defined at smtp190.com.
Question and response
Question
dig mx1.smtp190.com. NS
Answer
The response has no answer records.
Authority
smtp190.com. 300 SOA x.ns.joker.com. hostmaster.joker.com. 2025111453 14400 3600 1209600 300
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0