postoffice.mx71.net has no MX records.
Question and response
Question
dig mailcow.mx71.net. MX
Answer
The response has no answer records.
Authority
mx71.net. 86400 SOA ns1.ns71.net. domadm.ketele.at. 2025112605 28800 7200 1209600 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0