Apex domains cannot have CNAME records.
Question and response
Question
dig virtu.nl. NS
Answer
virtu.nl. 5 NS ns2.virtu.nl.
virtu.nl. 5 NS adns1.virtu.nl.
Authority
The response has no authority records.
Additional
ns2.virtu.nl. 5 A 94.103.17.2
adns1.virtu.nl. 5 A 77.222.73.2
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0