bulk02.brennercom.net has no CNAME records.
Question and response
Question
dig bulk02.brennercom.net. NS
Answer
The response has no answer records.
Authority
brennercom.net. 1666 SOA marek.ns.cloudflare.com. dns.cloudflare.com. 2397242853 10000 2400 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0