Apex domains cannot have CNAME records.
Question and response
Question
dig libello.com. NS
Answer
libello.com. 3 NS ns2.monaco-telecom.net.
libello.com. 3 NS ns1.monaco-telecom.mc.
Authority
The response has no authority records.
Additional
ns1.monaco-telecom.mc. 2 A 195.78.6.36
ns2.monaco-telecom.net. 3 A 195.78.6.210
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0