Apex domains cannot have CNAME records.
Question and response
Question
dig dgtek.net. NS
Answer
dgtek.net. 4 NS ns-78.awsdns-09.com.
dgtek.net. 4 NS ns-1911.awsdns-46.co.uk.
dgtek.net. 4 NS ns-1526.awsdns-62.org.
dgtek.net. 4 NS ns-860.awsdns-43.net.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0