mx3.ennit.net has no CNAME records.
Question and response
Question
dig mx3.ennit.net. NS
Answer
The response has no answer records.
Authority
ennit.net. 283 SOA ns1.ennit.net. hostmaster.support.ennit.de. 2026022001 14400 7200 3600000 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0