Apex domains cannot have CNAME records.
Question and response
Question
dig ihg.com. NS
Answer
ihg.com. 5 NS a9-66.akam.net.
ihg.com. 5 NS a1-131.akam.net.
ihg.com. 5 NS a16-66.akam.net.
ihg.com. 5 NS a26-67.akam.net.
ihg.com. 5 NS a4-64.akam.net.
ihg.com. 5 NS a5-65.akam.net.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0