Apex domains cannot have CNAME records.
Question and response
Question
dig insite.pl. NS
Answer
insite.pl. 5 NS ns2.insite.pl.
insite.pl. 5 NS ns1.insite.pl.
Authority
The response has no authority records.
Additional
ns1.insite.pl. 5 A 78.155.96.226
ns2.insite.pl. 5 A 193.239.206.249
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0