Apex domains cannot have CNAME records.
Question and response
Question
dig p.lodz.pl. NS
Answer
p.lodz.pl. 5 NS dns3.p.lodz.pl.
p.lodz.pl. 5 NS dns2.p.lodz.pl.
p.lodz.pl. 5 NS dns1.p.lodz.pl.
p.lodz.pl. 5 NS dns5.man.lodz.pl.
Authority
The response has no authority records.
Additional
dns1.p.lodz.pl. 5 A 212.51.207.70
dns2.p.lodz.pl. 5 A 212.51.207.68
dns3.p.lodz.pl. 5 A 212.51.207.69
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0