Apex domains cannot have CNAME records.
Question and response
Question
dig rcs.it. NS
Answer
rcs.it. 5 NS dnsgeo8.tuonomeregistrar.info.
rcs.it. 5 NS dnsgeo5.tuonomeregistrar.com.
rcs.it. 5 NS dnsgeo6.tuonomeregistrar.net.
rcs.it. 5 NS dnsgeo7.tuonomeregistrar.org.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0