uk2.smtp.exclaimer.net has no MX records.
Question and response
Question
dig uk2.smtp.exclaimer.net. MX
Answer
The response has no answer records.
Authority
exclaimer.net. 1800 SOA javon.ns.cloudflare.com. dns.cloudflare.com. 2397499328 10000 2400 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0