Apex domains cannot have CNAME records.
Question and response
Question
dig altimber.com. NS
Answer
altimber.com. 5 NS ns1.dondominio.com.
altimber.com. 5 NS ns2.dondominio.com.
Authority
The response has no authority records.
Additional
ns1.dondominio.com. 5 A 87.117.96.2
ns2.dondominio.com. 5 A 87.117.96.3
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0