mx.zerotimeservices.com has no CNAME records.
Question and response
Question
dig mx.zerotimeservices.com. NS
Answer
The response has no answer records.
Authority
zerotimeservices.com. 3384 SOA ns1.zerotimeservices.com. postmaster.zerotimeservices.com. 2025102801 3600 3600 1209600 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0