dns2.futuro.pl has no CNAME records.
Question and response
Question
dig dns2.futuro.pl. NS
Answer
The response has no answer records.
Authority
futuro.pl. 10800 SOA szafir.futuro.pl. dns.netia.pl. 2021111501 3600 1800 1814400 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0