static.highway.a1.net has no MX records.
Question and response
Question
dig static.highway.a1.net. MX
Answer
The response has no answer records.
Authority
static.highway.a1.net. 604800 SOA dns4.a1.net. domainadmin.a1.net. 2025071700 86400 3600 3600000 604800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0