Apex domains cannot have CNAME records.
Question and response
Question
dig samen-wonen.org. NS
Answer
samen-wonen.org. 5 NS ns-866.awsdns-44.net.
samen-wonen.org. 5 NS ns-1072.awsdns-06.org.
samen-wonen.org. 5 NS ns-1567.awsdns-03.co.uk.
samen-wonen.org. 5 NS ns-1962.awsdns-53.co.uk.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0