Apex domains cannot have CNAME records.
Question and response
Question
dig one.com. NS
Answer
one.com. 2 NS auth.g1-dns.one.
one.com. 2 NS auth.g1-dns.com.
Authority
The response has no authority records.
Additional
auth.g1-dns.com. 2 A 195.206.121.11
auth.g1-dns.one. 2 A 185.10.11.11
auth.g1-dns.com. 2 AAAA 2001:67c:28cc:0:0:0:0:11
auth.g1-dns.one. 2 AAAA 2001:67c:3c0:0:0:0:0:11
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0