Apex domains cannot have CNAME records.
Question and response
Question
dig suchdol.net. NS
Answer
suchdol.net. 1 NS ns2.dacc.cz.
suchdol.net. 1 NS ns1.dacc.cz.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0