Apex domains cannot have CNAME records.
Question and response
Question
dig xbiz.ne.jp. NS
Answer
xbiz.ne.jp. 5 NS ns2.xbiz.ne.jp.
xbiz.ne.jp. 5 NS ns1.xbiz.ne.jp.
xbiz.ne.jp. 5 NS ns3.xbiz.ne.jp.
Authority
The response has no authority records.
Additional
ns1.xbiz.ne.jp. 5 A 157.112.182.247
ns2.xbiz.ne.jp. 5 A 35.76.79.244
ns3.xbiz.ne.jp. 5 A 157.112.191.237
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0