Apex domains cannot have CNAME records.
Question and response
Question
dig mio-vicino.com. NS
Answer
mio-vicino.com. 5 NS ns-422.awsdns-52.com.
mio-vicino.com. 5 NS ns-114.awsdns-14.com.
mio-vicino.com. 5 NS ns-1211.awsdns-23.org.
mio-vicino.com. 5 NS ns-926.awsdns-51.net.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0