custmx-spf.aax2.net has no CNAME records.
Question and response
Question
dig custmx-spf.aax2.net. NS
Answer
The response has no answer records.
Authority
aax2.net. 3817 SOA ns1.compax.at. hostmaster.compax.at. 2026030300 28800 7200 604800 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0