www.lumen.com has no MX records.
Question and response
Question
dig adobe-aem.map.fastly.net. MX
Answer
The response has no answer records.
Authority
fastly.net. 30 SOA ns1.fastly.net. hostmaster.fastly.com. 2017052201 3600 600 604800 30
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0