mail.moweb.jp has no CNAME records.
Question and response
Question
dig mail.moweb.jp. NS
Answer
The response has no answer records.
Authority
moweb.jp. 2560 SOA ns.jp.betrend.com. bt_mis.betrend.com. 1772176435 16384 2048 1048576 2560
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0