ns1.16clouds.com has no MX records.
Question and response
Question
dig ns1.16clouds.com. MX
Answer
The response has no answer records.
Authority
ns1.16clouds.com. 43200 SOA ns1.16clouds.com. mail.localhost. 2026022201 43200 7200 1800000 43200
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0