Apex domains cannot have CNAME records.
Question and response
Question
dig pipenitro.com. NS
Answer
pipenitro.com. 5 NS ns2.pipenitro.com.
pipenitro.com. 5 NS ns1.pipenitro.com.
Authority
The response has no authority records.
Additional
ns1.pipenitro.com. 5 A 5.135.31.111
ns2.pipenitro.com. 5 A 51.77.98.179
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0