klient.box3.pl has no CNAME records.
Question and response
Question
dig klient.box3.pl. NS
Answer
The response has no answer records.
Authority
box3.pl. 3600 SOA dns1.box3.pl. hostmaster.box3.pl. 2026020115 3600 3600 1209600 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0