Apex domains cannot have CNAME records.
Question and response
Question
dig pamico.cz. NS
Answer
pamico.cz. 5 NS ns2-auth.pamico-czech.cz.
pamico.cz. 5 NS ns1-auth.pamico-czech.cz.
Authority
The response has no authority records.
Additional
ns1-auth.pamico-czech.cz. 5 A 185.147.250.20
ns2-auth.pamico-czech.cz. 5 A 185.147.250.21
ns1-auth.pamico-czech.cz. 5 AAAA 2a07:58c0:0:20:0:0:0:1
ns2-auth.pamico-czech.cz. 5 AAAA 2a07:58c0:0:21:0:0:0:1
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0