Apex domains cannot have CNAME records.
Question and response
Question
dig terminal.cz. NS
Answer
terminal.cz. 5 NS dns.terminal.cz.
terminal.cz. 5 NS sns.terminal.cz.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0