Apex domains cannot have CNAME records.
Question and response
Question
dig heteml.jp. NS
Answer
heteml.jp. 5 NS dns0.heteml.jp.
heteml.jp. 5 NS dns1.heteml.jp.
Authority
The response has no authority records.
Additional
dns0.heteml.jp. 5 A 157.7.44.53
dns1.heteml.jp. 5 A 157.7.188.149
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0