ui-dns.org has no MX records.
Question and response
Question
dig ui-dns.org. MX
Answer
The response has no answer records.
Authority
ui-dns.org. 600 SOA ns-org.ui-dns.org. dnsadmin.ionos.com. 2011021977 28800 7200 604800 600
Additional
. 0 OPT ; payload 1220, xrcode 0, version 0, flags 0