mx.sldc.pl has no NS records.
NS records for this zone are defined at sldc.pl.
NS records for this zone are defined at sldc.pl.
Question and response
Question
dig mx.sldc.pl. NS
Answer
The response has no answer records.
Authority
sldc.pl. 100 SOA dns1.slaskdatacenter.pl. admin.slaskdatacenter.pl. 2023051520 100 100 100 100
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0