mx.rodeohuntsville.com has no CNAME records.
Question and response
Question
dig mx.rodeohuntsville.com. NS
Answer
The response has no answer records.
Authority
rodeohuntsville.com. 6 SOA dns.rodeohuntsville.com. hostmaster.rodeohuntsville.com. 1200213098 43200 3600 604800 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0