Apex domains cannot have CNAME records.
Question and response
Question
dig ndltr.cn. NS
Answer
ndltr.cn. 1 NS veronica.ns.cloudflare.com.
ndltr.cn. 1 NS viddy.ns.cloudflare.com.
Authority
The response has no authority records.
Additional
viddy.ns.cloudflare.com. 3 A 108.162.195.99
viddy.ns.cloudflare.com. 3 A 162.159.44.99
viddy.ns.cloudflare.com. 3 A 172.64.35.99
veronica.ns.cloudflare.com. 3 A 108.162.194.173
veronica.ns.cloudflare.com. 3 A 162.159.38.173
veronica.ns.cloudflare.com. 3 A 172.64.34.173
viddy.ns.cloudflare.com. 3 AAAA 2606:4700:58:0:0:0:a29f:2c63
viddy.ns.cloudflare.com. 3 AAAA 2803:f800:50:0:0:0:6ca2:c363
viddy.ns.cloudflare.com. 3 AAAA 2a06:98c1:50:0:0:0:ac40:2363
veronica.ns.cloudflare.com. 3 AAAA 2606:4700:50:0:0:0:a29f:26ad
veronica.ns.cloudflare.com. 3 AAAA 2803:f800:50:0:0:0:6ca2:c2ad
veronica.ns.cloudflare.com. 3 AAAA 2a06:98c1:50:0:0:0:ac40:22ad
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0