mx1.domainlocalhost.com has no CNAME records.
Question and response
Question
dig mx1.domainlocalhost.com. NS
Answer
The response has no answer records.
Authority
domainlocalhost.com. 2630 SOA ns1.mycloudmailbox.com. admin\@sherweb.com. 55587 1800 300 604800 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0