mx.maxf.net has no CNAME records.
Question and response
Question
dig mx.maxf.net. NS
Answer
The response has no answer records.
Authority
maxf.net. 580 SOA maxf.net. dns.maxf.net. 1770158386 600 600 604800 600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0