Apex domains cannot have CNAME records.
Question and response
Question
dig azure-dns.org. NS
Answer
azure-dns.org. 5 NS ns3-01.azure-dns.org.
azure-dns.org. 5 NS ns11-201.azure-dns.org.
azure-dns.org. 5 NS ns11-01.azure-dns.org.
azure-dns.org. 5 NS ns3-03.azure-dns.org.
azure-dns.org. 5 NS ns3-32.azure-dns.org.
azure-dns.org. 5 NS ns3-04.azure-dns.org.
azure-dns.org. 5 NS ns3-64.azure-dns.org.
azure-dns.org. 5 NS ns3-02.azure-dns.org.
Authority
The response has no authority records.
Additional
ns3-01.azure-dns.org. 5 A 204.14.183.1
ns3-02.azure-dns.org. 5 A 204.14.183.2
ns3-03.azure-dns.org. 5 A 204.14.183.3
ns3-04.azure-dns.org. 5 A 204.14.183.4
ns3-01.azure-dns.org. 5 AAAA 2a01:111:4000:700:0:0:0:1
ns3-02.azure-dns.org. 5 AAAA 2a01:111:4000:700:0:0:0:2
ns3-03.azure-dns.org. 5 AAAA 2a01:111:4000:700:0:0:0:3
ns3-04.azure-dns.org. 5 AAAA 2a01:111:4000:700:0:0:0:4
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0