Apex domains cannot have CNAME records.
Question and response
Question
dig web-01.dejvishost.eu. NS
Answer
web-01.dejvishost.eu. 5 NS ns2.dejvishost.eu.
web-01.dejvishost.eu. 5 NS ns3.dejvishost.eu.
web-01.dejvishost.eu. 5 NS ns1.dejvishost.eu.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0