Apex domains cannot have CNAME records.
Question and response
Question
dig atman.pl. NS
Answer
atman.pl. 5 NS dns2.atman.pl.
atman.pl. 5 NS dns.atman.pl.
Authority
The response has no authority records.
Additional
dns.atman.pl. 5 A 85.232.226.102
dns2.atman.pl. 5 A 77.79.235.102
dns.atman.pl. 5 AAAA 2001:1a68:0:0:0:0:55e8:e266
dns2.atman.pl. 5 AAAA 2001:1a68:0:0:0:0:4d4f:eb66
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0