Apex domains cannot have CNAME records.
Question and response
Question
dig fastservers.net. NS
Answer
fastservers.net. 5 NS ns3.datapipe.net.
fastservers.net. 5 NS ns1.datapipe.net.
fastservers.net. 5 NS ns2.datapipe.net.
fastservers.net. 5 NS ns4.datapipe.net.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0