mail.finaltek.com has no CNAME records.
Question and response
Question
dig mail.finaltek.com. NS
Answer
The response has no answer records.
Authority
finaltek.com. 1800 SOA ns.gransy.com. root.gransy.com. 2767534826 86400 900 1209600 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0