mx.premium.pl has no NS records.
NS records for this zone are defined at premium.pl.
NS records for this zone are defined at premium.pl.
Question and response
Question
dig mx.premium.pl. NS
Answer
The response has no answer records.
Authority
premium.pl. 3600 SOA dns.home.pl. admin.home.pl. 1570187690 14400 7200 2419200 3600
Additional
. 0 OPT ; payload 1220, xrcode 0, version 0, flags 0