mx.firesidekc.com has no CNAME records.
Question and response
Question
dig mx.firesidekc.com. NS
Answer
The response has no answer records.
Authority
firesidekc.com. 3317 SOA dns.firesidekc.com. hostmaster.firesidekc.com. 1487281096 43200 3600 604800 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0