Apex domains cannot have CNAME records.
Question and response
Question
dig n123.domenomania.pl. NS
Answer
n123.domenomania.pl. 5 NS ns1.prociv.com.
n123.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