mxb.dnsdrift.net has no CNAME records.
Question and response
Question
dig mxb.dnsdrift.net. NS
Answer
The response has no answer records.
Authority
dnsdrift.net. 8224 SOA ns.dnsdrift.net. registry.exeo.se. 1772542619 3600 3600 604800 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0