Apex domains cannot have CNAME records.
Question and response
Question
dig project4.pl. NS
Answer
project4.pl. 5 NS ns3.project4.pl.
project4.pl. 5 NS kirdan.nask.net.pl.
project4.pl. 5 NS ns1.project4.pl.
project4.pl. 5 NS ns2.project4.pl.
project4.pl. 5 NS dns2.atman.pl.
Authority
The response has no authority records.
Additional
ns1.project4.pl. 5 A 89.108.195.18
ns2.project4.pl. 5 A 89.108.195.19
ns3.project4.pl. 5 A 89.108.202.18
dns2.atman.pl. 5 A 77.79.235.102
dns2.atman.pl. 5 AAAA 2001:1a68:0:0:0:0:4d4f:eb66
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0