_ssf2f3yot2.sdmarc.net has no MX records.
Question and response
Question
dig _ssf2f3yot2.sdmarc.net. MX
Answer
The response has no answer records.
Authority
sdmarc.net. 1800 SOA ns1.sendmarc.net. dns.cloudflare.com. 2397441161 10000 2400 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0