mx01.dondominio.com has no MX records.
Question and response
Question
dig mx01.dondominio.com. MX
Answer
The response has no answer records.
Authority
dondominio.com. 60 SOA ns1.dondominio.com. dnsadmin.dondominio.com. 2026021800 10800 1800 691200 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0