ns.watson.ibm.com has no MX records.
Question and response
Question
dig ns.watson.ibm.com. MX
Answer
The response has no answer records.
Authority
watson.ibm.com. 900 SOA dns1.p05.nsone.net. hostmaster.nsone.net. 1729786484 3600 3600 2419200 900
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0