mx.hack8pool.com has no CNAME records.
Question and response
Question
dig mx.hack8pool.com. NS
Answer
The response has no answer records.
Authority
hack8pool.com. 3578 SOA dns.hack8pool.com. hostmaster.hack8pool.com. 1112415067 43200 3600 604800 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0