mx.jazzimprovisation-video.com has no CNAME records.
Question and response
Question
dig mx.jazzimprovisation-video.com. NS
Answer
The response has no answer records.
Authority
jazzimprovisation-video.com. 3472 SOA dns.jazzimprovisation-video.com. hostmaster.jazzimprovisation-video.com. 1958389166 43200 3600 604800 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0