mx1.sendclean.email has no MX records.
Question and response
Question
dig mx1.sendclean.email. MX
Answer
The response has no answer records.
Authority
sendclean.email. 1800 SOA aryanna.ns.cloudflare.com. dns.cloudflare.com. 2397014374 10000 2400 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0