mail.blnkserver.com has no CNAME records.
Question and response
Question
dig mail.blnkserver.com. NS
Answer
The response has no answer records.
Authority
blnkserver.com. 5130 SOA blnkserver.com. admin.benosborne.com. 2025081911 86400 7200 2419200 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0