mpls.qwest.net has no MX records.
Question and response
Question
dig mpls.qwest.net. MX
Answer
The response has no answer records.
Authority
mpls.qwest.net. 300 SOA authns1.qwest.net. abuse.aup.lumen.com. 2240730002 10800 3600 604800 300
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0