webmail.he-roes.de has no CNAME records.
Question and response
Question
dig webmail.he-roes.de. NS
Answer
The response has no answer records.
Authority
he-roes.de. 300 SOA ns1031.ui-dns.com. hostmaster.1and1.com. 2017060688 28800 7200 604800 300
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0