mx3.mein-mailgateway.de has no CNAME records.
Question and response
Question
dig mx3.mein-mailgateway.de. NS
Answer
The response has no answer records.
Authority
mein-mailgateway.de. 3525 SOA ns1.mein-webdienst.de. hostmaster.mein-webdienst.de. 2025111103 10800 3600 604800 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0