mail300.plma.se has no MX records.
Question and response
Question
dig mail300.plma.se. MX
Answer
The response has no answer records.
Authority
plma.se. 3600 SOA dns9.telia.com. backbone.telia.net. 1772064000 21600 7200 604800 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0