librenms.net.deic.dk has no MX records.
Question and response
Question
dig librenms.net.deic.dk. MX
Answer
The response has no answer records.
Authority
deic.dk. 3600 SOA mimer.deic.dk. dns.darenet.dk. 1771846732 16384 2048 2097152 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0