ns4.brcc.digital-delivery.com has no MX records.
Question and response
Question
dig ns4.brcc.digital-delivery.com. MX
Answer
The response has no answer records.
Authority
brcc.digital-delivery.com. 3600 SOA edns1.ultradns.com. enterprisedns.broadridge.com. 2019092834 86400 86400 86400 3600
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0