Apex domains cannot have CNAME records.
Question and response
Question
dig aics.ad.jp. NS
Answer
aics.ad.jp. 5 NS ns13.aics.ad.jp.
aics.ad.jp. 5 NS ns12.aics.ad.jp.
aics.ad.jp. 5 NS ns11.aics.ad.jp.
Authority
The response has no authority records.
Additional
ns11.aics.ad.jp. 5 A 157.205.57.3
ns12.aics.ad.jp. 5 A 157.205.57.67
ns13.aics.ad.jp. 5 A 157.205.57.131
ns11.aics.ad.jp. 5 AAAA 2403:6c00:100a:3900:0:0:0:3
ns12.aics.ad.jp. 5 AAAA 2403:6c00:100a:3940:0:0:0:67
ns13.aics.ad.jp. 5 AAAA 2403:6c00:100a:3980:0:0:0:131
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0