dns1.small-dns.com has no MX records.
Question and response
Question
dig dns1.small-dns.com. MX
Answer
The response has no answer records.
Authority
small-dns.com. 1800 SOA dns1.small-dns.com. root.small-dns.com. 1704202106 7200 300 1209600 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0