Apex domains cannot have CNAME records.
Question and response
Question
dig costumes-suisse.com. NS
Answer
costumes-suisse.com. 5 NS ns-244.awsdns-30.com.
costumes-suisse.com. 5 NS ns-1290.awsdns-33.org.
costumes-suisse.com. 5 NS ns-870.awsdns-44.net.
costumes-suisse.com. 5 NS ns-1633.awsdns-12.co.uk.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0