spf.easybill-mail.de has no CNAME records.
Question and response
Question
dig spf.easybill-mail.de. NS
Answer
The response has no answer records.
Authority
easybill-mail.de. 2708 SOA a.ns14.net. cs.easybill.de. 2025081903 43200 7200 1209600 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0