mx.yotta.com has no CNAME records.
Question and response
Question
dig mx.yotta.com. NS
Answer
The response has no answer records.
Authority
yotta.com. 3228 SOA ns1.yotta.com. root\@ns1.yotta.com. 2026021201 28800 7200 604800 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0