Apex domains cannot have CNAME records.
Question and response
Question
dig scutum.jp. NS
Answer
scutum.jp. 3 NS ns-1.awsdns-00.com.
scutum.jp. 3 NS ns-611.awsdns-12.net.
scutum.jp. 3 NS ns-1060.awsdns-04.org.
scutum.jp. 3 NS ns-1593.awsdns-07.co.uk.
Authority
The response has no authority records.
Additional
ns-1.awsdns-00.com. 4 A 205.251.192.1
ns-611.awsdns-12.net. 4 A 205.251.194.99
ns-1060.awsdns-04.org. 4 A 205.251.196.36
ns-1593.awsdns-07.co.uk. 4 A 205.251.198.57
ns-1.awsdns-00.com. 4 AAAA 2600:9000:5300:100:0:0:0:1
ns-611.awsdns-12.net. 4 AAAA 2600:9000:5302:6300:0:0:0:1
ns-1060.awsdns-04.org. 4 AAAA 2600:9000:5304:2400:0:0:0:1
ns-1593.awsdns-07.co.uk. 4 AAAA 2600:9000:5306:3900:0:0:0:1
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0