Apex domains cannot have CNAME records.
Question and response
Question
dig ortopediaroma.com. NS
Answer
ortopediaroma.com. 5 NS ns-277.awsdns-34.com.
ortopediaroma.com. 5 NS ns-1087.awsdns-07.org.
ortopediaroma.com. 5 NS ns-981.awsdns-58.net.
ortopediaroma.com. 5 NS ns-1790.awsdns-31.co.uk.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0