mx.quail-peak.com has no CNAME records.
Question and response
Question
dig mx.quail-peak.com. NS
Answer
The response has no answer records.
Authority
quail-peak.com. 3563 SOA dns.quail-peak.com. hostmaster.quail-peak.com. 1911679525 43200 3600 604800 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0