Apex domains cannot have CNAME records.
Question and response
Question
dig ispsupport.com. NS
Answer
ispsupport.com. 5 NS ns1.ispsupport.com.
ispsupport.com. 5 NS ns2.ispsupport.com.
Authority
The response has no authority records.
Additional
ns1.ispsupport.com. 5 A 216.55.97.117
ns2.ispsupport.com. 5 A 216.55.98.117
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0