Apex domains cannot have CNAME records.
Question and response
Question
dig n124.domenomania.pl. NS
Answer
n124.domenomania.pl. 5 NS ns1.prociv.com.
n124.domenomania.pl. 5 NS ns2.prociv.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0