gbgsmtp.dgc.se has no MX records.
Question and response
Question
dig gbgsmtp.dgc.se. MX
Answer
The response has no answer records.
Authority
dgc.se. 60 SOA ns1.dgcsystems.net. registry.dgc.se. 3034589454 10800 3600 604800 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0