insecure.branding.arnsbomedia.com has no MX records.
Question and response
Question
dig a87.dscg10.akamai.net. MX
Answer
The response has no answer records.
Authority
dscg10.akamai.net. 1000 SOA n0dscg10.akamai.net. hostmaster.akamai.com. 1772926142 1000 1000 1000 1800
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0