mx.i.bitbit.net has no CNAME records.
Question and response
Question
dig mx.i.bitbit.net. NS
Answer
The response has no answer records.
Authority
i.bitbit.net. 3386 SOA ns-foo.i.bitbit.net. hostmaster.redpill-linpro.com. 2019045448 10800 3600 2419200 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0