Apex domains cannot have CNAME records.
Question and response
Question
dig vigrxplus-reviews.com. NS
Answer
vigrxplus-reviews.com. 5 NS ns-264.awsdns-33.com.
vigrxplus-reviews.com. 5 NS ns-1722.awsdns-23.co.uk.
vigrxplus-reviews.com. 5 NS ns-828.awsdns-39.net.
vigrxplus-reviews.com. 5 NS ns-1910.awsdns-46.co.uk.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0