spf.enbw.com has no MX records.
Question and response
Question
dig spf.enbw.com. MX
Answer
The response has no answer records.
Authority
enbw.com. 10800 SOA nss01.enbw.com. hostmaster.enbw.com. 2026021901 10800 3600 604800 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0