Apex domains cannot have CNAME records.
Question and response
Question
dig gemini.oneoffice.jp. NS
Answer
gemini.oneoffice.jp. 5 NS ns005-gf00vthn5a665c9d.g.d-53.info.
gemini.oneoffice.jp. 5 NS ns005-gf00vthn5a665c9d.g.d-53.jp.
gemini.oneoffice.jp. 5 NS ns005-gf00vthn5a665c9d.g.d-53.net.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0