mail.twoople.com has no CNAME records.
Question and response
Question
dig mail.twoople.com. NS
Answer
The response has no answer records.
Authority
twoople.com. 338 SOA a.share-dns.com. master.share-dns.com. 1765260472 3600 1200 86400 600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0