Apex domains cannot have CNAME records.
Question and response
Question
dig mss.mind.ne.jp. NS
Answer
mss.mind.ne.jp. 4 NS ns1.mss.mind.ne.jp.
mss.mind.ne.jp. 4 NS ns21.sc24.jp.
Authority
The response has no authority records.
Additional
ns1.mss.mind.ne.jp. 4 A 210.172.237.70
ns21.sc24.jp. 4 A 203.178.75.166
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0