mx.zoho.co.jp has no CNAME records.
Question and response
Question
dig mx.zoho.co.jp. NS
Answer
The response has no answer records.
Authority
zoho.co.jp. 300 SOA 01.dnsv.jp. hostmaster.dnsv.jp. 1771926162 3600 900 604800 300
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0