Apex domains cannot have CNAME records.
Question and response
Question
dig intertune.com. NS
Answer
intertune.com. 5 NS ns-1493.awsdns-58.org.
intertune.com. 5 NS ns-1818.awsdns-35.co.uk.
intertune.com. 5 NS ns-130.awsdns-16.com.
intertune.com. 5 NS ns-555.awsdns-05.net.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0