Apex domains cannot have CNAME records.
Question and response
Question
dig doctorout.com. NS
Answer
doctorout.com. 5 NS ns1.doctorout.com.
doctorout.com. 5 NS ns2.doctorout.com.
Authority
The response has no authority records.
Additional
ns1.doctorout.com. 5 A 170.130.202.46
ns2.doctorout.com. 5 A 173.44.158.38
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0