Apex domains cannot have CNAME records.
Question and response
Question
dig azia.jp. NS
Answer
azia.jp. 5 NS dns2.azia.co.jp.
azia.jp. 5 NS dns3.odn.ne.jp.
azia.jp. 5 NS dns1.azia.co.jp.
Authority
The response has no authority records.
Additional
dns1.azia.co.jp. 5 A 219.101.179.195
dns2.azia.co.jp. 5 A 219.101.179.194
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0