Apex domains cannot have CNAME records.
Question and response
Question
dig mastercardaem.com. NS
Answer
mastercardaem.com. 5 NS a9-64.akam.net.
mastercardaem.com. 5 NS a7-67.akam.net.
mastercardaem.com. 5 NS a1-29.akam.net.
mastercardaem.com. 5 NS a26-66.akam.net.
mastercardaem.com. 5 NS a22-65.akam.net.
mastercardaem.com. 5 NS a18-64.akam.net.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0