mx01.qfast.net has no CNAME records.
Question and response
Question
dig mx01.qfast.net. NS
Answer
The response has no answer records.
Authority
qfast.net. 3547 SOA ns1.dnszones.eu. hostmaster.dnszones.eu. 2022102562 28800 7200 604800 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0