Apex domains cannot have CNAME records.
Question and response
Question
dig 064a.241.221.202.in-addr.arpa. NS
Answer
064a.241.221.202.in-addr.arpa. 4 NS dns2.interlink.or.jp.
064a.241.221.202.in-addr.arpa. 4 NS dns1.interlink.or.jp.
Authority
The response has no authority records.
Additional
dns1.interlink.or.jp. 4 A 203.141.128.37
dns2.interlink.or.jp. 4 A 163.43.145.12
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0