Apex domains cannot have CNAME records.
Question and response
Question
dig heightspropsol.com. NS
Answer
heightspropsol.com. 5 NS ns-1661.awsdns-15.co.uk.
heightspropsol.com. 5 NS ns-348.awsdns-43.com.
heightspropsol.com. 5 NS ns-494.awsdns-61.com.
heightspropsol.com. 5 NS ns-1884.awsdns-43.co.uk.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0