mail.halden.net has no MX records.
Question and response
Question
dig mail.halden.net. MX
Answer
The response has no answer records.
Authority
halden.net. 360 SOA ns1.halden.net. hostmaster.halden.net. 2026020902 3600 600 86400 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0