Apex domains cannot have CNAME records.
Question and response
Question
dig pdiphotos.com. NS
Answer
pdiphotos.com. 5 NS ns-110.awsdns-13.com.
pdiphotos.com. 5 NS ns-1203.awsdns-22.org.
pdiphotos.com. 5 NS ns-1027.awsdns-00.org.
pdiphotos.com. 5 NS ns-1560.awsdns-03.co.uk.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0