ns2.siteground.us has no MX records.
Question and response
Question
dig ns2.siteground.us. MX
Answer
The response has no answer records.
Authority
siteground.us. 14400 SOA ns1.siteground.net. msi200.siteground.com. 2009030128 14400 7200 3600000 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0