Apex domains cannot have CNAME records.
Question and response
Question
dig isp.servpersosystems.net. NS
Answer
isp.servpersosystems.net. 5 NS ns2-ipam.servperso.net.
isp.servpersosystems.net. 5 NS ns1-ipam.servperso.net.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0