mail.a2zcreatorz.com has no CNAME records.
Question and response
Question
dig mail.a2zcreatorz.com. NS
Answer
The response has no answer records.
Authority
a2zcreatorz.com. 1151 SOA mona.ns.cloudflare.com. dns.cloudflare.com. 2398054615 10000 2400 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0