Apex domains cannot have CNAME records.
Question and response
Question
dig webserversystems.com. NS
Answer
webserversystems.com. 1 NS secondary.webserversystems.com.
webserversystems.com. 1 NS primary.webserversystems.com.
Authority
The response has no authority records.
Additional
primary.webserversystems.com. 1 A 162.215.1.175
secondary.webserversystems.com. 1 A 162.215.1.181
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0