mx.ondonator.se has no CNAME records.
Question and response
Question
dig mx.ondonator.se. NS
Answer
The response has no answer records.
Authority
ondonator.se. 2960 SOA ns1.iplace.se. registry.iplace.se. 2025071601 10800 3600 604800 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0