_spf.mx71.net has no MX records.
Question and response
Question
dig _spf.mx71.net. MX
Answer
The response has no answer records.
Authority
mx71.net. 86400 SOA ns1.ns71.net. domadm.ketele.at. 2026020302 28800 7200 1209600 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0