mx2.emailsrvr.com has no MX records.
Question and response
Question
dig mx2.emailsrvr.com. MX
Answer
The response has no answer records.
Authority
mx2.emailsrvr.com. 300 SOA ns.rackspace.com. postmaster.emailsrvr.com. 1685284055 3600 300 1814400 300
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0