d0.pr.afilias-nst.org has no MX records.
Question and response
Question
dig d0.pr.afilias-nst.org. MX
Answer
The response has no answer records.
Authority
pr.afilias-nst.org. 86400 SOA . noc.afilias-nst.info. 2017110700 10800 3600 2592000 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0