poczta.sprint.pl has no NS records.
NS records for this zone are defined at sprint.pl.
NS records for this zone are defined at sprint.pl.
Question and response
Question
dig poczta.sprint.pl. NS
Answer
The response has no answer records.
Authority
sprint.pl. 1800 SOA raquel.ns.cloudflare.com. dns.cloudflare.com. 2399320225 10000 2400 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0