Apex domains cannot have CNAME records.
Question and response
Question
dig altospam.eu. NS
Answer
altospam.eu. 5 NS ns-112-a.gandi.net.
altospam.eu. 5 NS ns-140-c.gandi.net.
altospam.eu. 5 NS ns-59-b.gandi.net.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0