mx1.besserwisser.org has no CNAME records.
Question and response
Question
dig mx1.besserwisser.org. NS
Answer
The response has no answer records.
Authority
besserwisser.org. 300 SOA primary.se. mansaxel.machina.se. 2026030502 301 3600 3600000 300
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0