mx1.iaires.com has no CNAME records.
Question and response
Question
dig mx1.iaires.com. NS
Answer
The response has no answer records.
Authority
iaires.com. 4955 SOA ns1.netcore.co.in. Postmaster.iaires.com. 446618595 900 3600 172800 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0