Apex domains cannot have CNAME records.
Question and response
Question
dig thinkface.com. NS
Answer
thinkface.com. 5 NS ns2.dnsexit.com.
thinkface.com. 5 NS ns4.dnsexit.com.
thinkface.com. 5 NS ns1.dnsexit.com.
thinkface.com. 5 NS ns3.dnsexit.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0