Apex domains cannot have CNAME records.
Question and response
Question
dig dn-s.org. NS
Answer
dn-s.org. 5 NS nsauth.dn-s.org.
dn-s.org. 5 NS nsauth.dn-s.be.
dn-s.org. 5 NS nsauth.dn-s.eu.
Authority
The response has no authority records.
Additional
nsauth.dn-s.be. 5 A 138.68.125.166
nsauth.dn-s.eu. 5 A 174.138.107.131
nsauth.dn-s.org. 5 A 185.104.28.40
nsauth.dn-s.eu. 5 AAAA 2a03:b0c0:2:d0:0:0:57:1002
nsauth.dn-s.org. 5 AAAA 2a06:2ec0:1:0:0:0:0:11
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0