smtp2004.sendmsg.jp has no CNAME records.
Question and response
Question
dig smtp2004.sendmsg.jp. NS
Answer
The response has no answer records.
Authority
sendmsg.jp. 2628 SOA ns01.idcfcloud.com. info.spf.sendmsg.jp. 449 10800 3600 604800 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0