Apex domains cannot have CNAME records.
Question and response
Question
dig dan.com. NS
Answer
dan.com. 5 NS a1-245.akam.net.
dan.com. 5 NS a11-64.akam.net.
dan.com. 5 NS a6-66.akam.net.
dan.com. 5 NS a9-67.akam.net.
dan.com. 5 NS a20-65.akam.net.
dan.com. 5 NS a8-67.akam.net.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0