de2.smtp.exclaimer.net has no CNAME records.
Question and response
Question
dig de2.smtp.exclaimer.net. NS
Answer
The response has no answer records.
Authority
exclaimer.net. 1800 SOA javon.ns.cloudflare.com. dns.cloudflare.com. 2398178561 10000 2400 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0