mail.monkeybrains.net has no CNAME records.
Question and response
Question
dig mail.monkeybrains.net. NS
Answer
The response has no answer records.
Authority
monkeybrains.net. 1804 SOA ns2.monkeybrains.NET. support.monkeybrains.NET. 2026022400 7200 1200 1209600 7200
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0