Apex domains cannot have CNAME records.
Question and response
Question
dig ip.cesenanet.net. NS
Answer
ip.cesenanet.net. 5 NS dns.ilmiofax.it.
ip.cesenanet.net. 5 NS dns2.cesenanet.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0