Apex domains cannot have CNAME records.
Question and response
Question
dig bluem.nl. NS
Answer
bluem.nl. 5 NS dns0.domeinbalie.nl.
bluem.nl. 5 NS dns2.domeinbalie.org.
bluem.nl. 5 NS dns1.domeinbalie.nl.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0