auth10.ns.wcom.com has no MX records.
Question and response
Question
dig auth10.ns.wcom.com. MX
Answer
The response has no answer records.
Authority
ns.wcom.com. 960 SOA omzdns9.verizon.com. hostmaster.mci.com. 1193 1920 960 604800 960
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0