Apex domains cannot have CNAME records.
Question and response
Question
dig bettina-stuurman-peintures.com. NS
Answer
bettina-stuurman-peintures.com. 4 NS ns1.bettina-stuurman-peintures.com.
bettina-stuurman-peintures.com. 4 NS ns2.bettina-stuurman-peintures.com.
Authority
The response has no authority records.
Additional
ns1.bettina-stuurman-peintures.com. 4 A 142.44.136.25
ns2.bettina-stuurman-peintures.com. 4 A 51.222.0.4
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0