mx1.ewetel.de has no CNAME records.
Question and response
Question
dig mx1.ewetel.de. NS
Answer
The response has no answer records.
Authority
ewetel.de. 5892 SOA ans0.ewetel.de. hostmaster.ewetel.de. 2026022235 10800 3600 604800 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0