mx.hercegolga.com has no NS records.
NS records for this zone are defined at hercegolga.com.
NS records for this zone are defined at hercegolga.com.
Question and response
Question
dig mx.hercegolga.com. NS
Answer
The response has no answer records.
Authority
hercegolga.com. 3600 SOA dns.hercegolga.com. hostmaster.hercegolga.com. 1928076773 43200 3600 604800 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0