mx1.cobytes.email has no CNAME records.
Question and response
Question
dig mx1.cobytes.email. NS
Answer
The response has no answer records.
Authority
cobytes.email. 300 SOA ns1.cobytes.io. hostmaster.cobytes.io. 2026011500 14400 3600 604800 300
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0