Apex domains cannot have CNAME records.
Question and response
Question
dig het.net.je. NS
Answer
het.net.je. 5 NS ns1.surfnet.nl.
het.net.je. 5 NS ns1.het.net.je.
Authority
The response has no authority records.
Additional
ns1.het.net.je. 5 A 192.87.110.29
ns1.surfnet.nl. 5 A 192.87.106.101
ns1.surfnet.nl. 5 AAAA 2001:610:1:800a:192:87:106:101
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0