pdns03.port53.se has no MX records.
Question and response
Question
dig pdns03.port53.se. MX
Answer
The response has no answer records.
Authority
port53.se. 600 SOA pdns01.port53.se. postmaster.port53.se. 2009101412 7200 1800 1209600 600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0