mail.a8e.de has no CNAME records.
Question and response
Question
dig mail.a8e.de. NS
Answer
The response has no answer records.
Authority
a8e.de. 55 SOA ns1.mainns.de. info.domains.resellerinterface.de. 1771292511 10800 3600 604800 120
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0