Apex domains cannot have CNAME records.
Question and response
Question
dig user.starcat.ne.jp. NS
Answer
user.starcat.ne.jp. 5 NS dns2.cnci.jp.
user.starcat.ne.jp. 5 NS dns1.cnci.jp.
user.starcat.ne.jp. 5 NS dns3.cnci.jp.
Authority
The response has no authority records.
Additional
dns1.cnci.jp. 4 A 210.158.149.11
dns2.cnci.jp. 4 A 210.158.149.12
dns3.cnci.jp. 4 A 210.158.148.72
dns1.cnci.jp. 4 AAAA 2405:7000:10:1:210:158:149:11
dns2.cnci.jp. 4 AAAA 2405:7000:10:1:210:158:149:12
dns3.cnci.jp. 4 AAAA 2405:7000:8:340c:0:0:0:8
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0