Apex domains cannot have CNAME records.
Question and response
Question
dig nuro.jp. NS
Answer
nuro.jp. 4 NS ns2.nuro.jp.
nuro.jp. 4 NS ns1.nuro.jp.
Authority
The response has no authority records.
Additional
ns1.nuro.jp. 4 A 118.238.201.34
ns2.nuro.jp. 4 A 118.238.201.50
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0