mail.wpxhosting.com has no CNAME records.
Question and response
Question
dig mail.wpxhosting.com. NS
Answer
The response has no answer records.
Authority
wpxhosting.com. 8124 SOA ns1.wpxhosting.com. root.v1.wpxhosting.com. 2026021805 10800 3600 604800 38400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0