Apex domains cannot have CNAME records.
Question and response
Question
dig vp-dns.net. NS
Answer
vp-dns.net. 5 NS deimos.vp-dns.net.
vp-dns.net. 5 NS phobos.vp-dns.net.
Authority
The response has no authority records.
Additional
deimos.vp-dns.net. 5 A 217.195.18.129
phobos.vp-dns.net. 5 A 217.195.17.18
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0