Apex domains cannot have CNAME records.
Question and response
Question
dig investis.com. NS
Answer
investis.com. 5 NS ns-1671.awsdns-16.co.uk.
investis.com. 5 NS ns-72.awsdns-09.com.
investis.com. 5 NS ns-934.awsdns-52.net.
investis.com. 5 NS ns-1338.awsdns-39.org.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0