mail2.memset.com has no MX records.
Question and response
Question
dig mail2.memset.com. MX
Answer
The response has no answer records.
Authority
memset.com. 2560 SOA ns1.memset.com. hostmaster.memset.com. 1771776016 16384 2048 1048576 2560
Additional
. 0 OPT ; payload 1680, xrcode 0, version 0, flags 0