Apex domains cannot have CNAME records.
Question and response
Question
dig comdataonline.com. NS
Answer
comdataonline.com. 2 NS azdns4.gotoweb.it.
comdataonline.com. 2 NS azdns1.konecta.it.
comdataonline.com. 2 NS azdns2.konecta.it.
comdataonline.com. 2 NS azdns3.gotoweb.it.
Authority
The response has no authority records.
Additional
azdns1.konecta.it. 2 A 51.124.136.34
azdns2.konecta.it. 2 A 51.124.136.35
azdns3.gotoweb.it. 2 A 20.105.112.10
azdns4.gotoweb.it. 2 A 20.105.112.11
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0