Apex domains cannot have CNAME records.
Question and response
Question
dig dnsnodes.com. NS
Answer
dnsnodes.com. 5 NS hela.dnsnodes.eu.
dnsnodes.com. 5 NS loki.dnsnodes.com.
dnsnodes.com. 5 NS thor.dnsnodes.eu.
dnsnodes.com. 5 NS odin.dnsnodes.eu.
dnsnodes.com. 5 NS frigg.dnsnodes.com.
Authority
The response has no authority records.
Additional
loki.dnsnodes.com. 5 A 194.58.196.61
frigg.dnsnodes.com. 5 A 217.79.214.245
loki.dnsnodes.com. 5 AAAA 2a01:3f1:863:0:0:0:0:53
frigg.dnsnodes.com. 5 AAAA 2a02:20a8:a000:4:0:0:0:2
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0