arsmtp.com has no MX records.
Question and response
Question
dig arsmtp.com. MX
Answer
The response has no answer records.
Authority
arsmtp.com. 600 SOA mdns1.appriver.com. support.appriver.com. 11121720 900 600 604800 600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0