Apex domains cannot have CNAME records.
Question and response
Question
dig dtiflash.com. NS
Answer
dtiflash.com. 5 NS ns-1725.awsdns-23.co.uk.
dtiflash.com. 5 NS ns-1738.awsdns-25.co.uk.
dtiflash.com. 5 NS ns-522.awsdns-01.net.
dtiflash.com. 5 NS ns-760.awsdns-31.net.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0