mail.memset.com has no CNAME records.
Question and response
Question
dig mail.memset.com. NS
Answer
The response has no answer records.
Authority
memset.com. 967 SOA ns1.memset.com. hostmaster.memset.com. 1771776914 16384 2048 1048576 2560
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0