mx.mymailserver.org has no CNAME records.
Question and response
Question
dig mx.mymailserver.org. NS
Answer
The response has no answer records.
Authority
mymailserver.org. 1690 SOA dns029.a.register.com. root.register.com. 2025071609 28800 7200 604800 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0