Apex domains cannot have CNAME records.
Question and response
Question
dig blnkserver.com. NS
Answer
blnkserver.com. 5 NS ns2.blnkserver.com.
blnkserver.com. 5 NS ns1.blnkserver.com.
Authority
The response has no authority records.
Additional
ns1.blnkserver.com. 5 A 74.201.177.85
ns2.blnkserver.com. 5 A 74.201.177.85
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0