mx.serlinastra.com has no NS records.
NS records for this zone are defined at serlinastra.com.
NS records for this zone are defined at serlinastra.com.
Question and response
Question
dig mx.serlinastra.com. NS
Answer
The response has no answer records.
Authority
serlinastra.com. 3600 SOA dns.serlinastra.com. hostmaster.serlinastra.com. 1795378766 43200 3600 604800 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0