dca-mail-01.oss.centurylink.net has no MX records.
Question and response
Question
dig dca-mail-01.oss.centurylink.net. MX
Answer
The response has no answer records.
Authority
oss.centurylink.net. 3600 SOA authns2.qwest.net. abuse.aup.lumen.com. 2260302000 10800 3600 604800 3600
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0