mx.vibefirewall.net has no CNAME records.
Question and response
Question
dig mx.vibefirewall.net. NS
Answer
The response has no answer records.
Authority
vibefirewall.net. 3362 SOA dns.vibefirewall.net. hostmaster.vibefirewall.net. 1712136431 43200 3600 604800 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0