spf.bert.group has no CNAME records.
Question and response
Question
dig spf.bert.group. NS
Answer
The response has no answer records.
Authority
bert.group. 7626 SOA ns1.arvato-systems.de. hostmaster.bnic.bertelsmann.de. 2026011300 86400 7200 3600000 172800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0