ns3.synchronoss.com has no MX records.
Question and response
Question
dig ns3.synchronoss.com. MX
Answer
The response has no answer records.
Authority
synchronoss.com. 900 SOA ns1.synchronoss.com. networkengineers.synchronoss.com. 812 10800 3600 604800 900
Additional
. 0 OPT ; payload 1220, xrcode 0, version 0, flags 0