Apex domains cannot have CNAME records.
Question and response
Question
dig izacom.pl. NS
Answer
izacom.pl. 5 NS dns102.ovh.net.
izacom.pl. 5 NS ns102.ovh.net.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0