Apex domains cannot have CNAME records.
Question and response
Question
dig mailds.jp. NS
Answer
mailds.jp. 4 NS rns1.rightsdns.com.
mailds.jp. 4 NS rns2.rightsdns.com.
Authority
The response has no authority records.
Additional
rns1.rightsdns.com. 4 A 34.97.240.47
rns2.rightsdns.com. 4 A 35.221.113.149
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0