Apex domains cannot have CNAME records.
Question and response
Question
dig xxx.afilias-nst.org. NS
Answer
xxx.afilias-nst.org. 4 NS d0.xxx.afilias-nst.org.
xxx.afilias-nst.org. 4 NS a2.xxx.afilias-nst.info.
xxx.afilias-nst.org. 4 NS b2.xxx.afilias-nst.org.
xxx.afilias-nst.org. 4 NS a0.xxx.afilias-nst.info.
xxx.afilias-nst.org. 4 NS b0.xxx.afilias-nst.org.
xxx.afilias-nst.org. 4 NS c0.xxx.afilias-nst.info.
Authority
The response has no authority records.
Additional
a0.xxx.afilias-nst.info. 4 A 199.115.152.1
a2.xxx.afilias-nst.info. 4 A 199.115.156.1
b0.xxx.afilias-nst.org. 4 A 199.115.153.1
c0.xxx.afilias-nst.info. 4 A 199.115.154.1
d0.xxx.afilias-nst.org. 4 A 199.115.155.1
a0.xxx.afilias-nst.info. 4 AAAA 2001:500:a0:0:0:0:0:1
a2.xxx.afilias-nst.info. 4 AAAA 2001:500:a4:0:0:0:0:1
b0.xxx.afilias-nst.org. 4 AAAA 2001:500:a1:0:0:0:0:1
c0.xxx.afilias-nst.info. 4 AAAA 2001:500:a2:0:0:0:0:1
d0.xxx.afilias-nst.org. 4 AAAA 2001:500:a3:0:0:0:0:1
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0