Apex domains cannot have CNAME records.
Question and response
Question
dig rr.com. NS
Answer
rr.com. 2 NS dns5.rr.com.
rr.com. 2 NS dns6.rr.com.
rr.com. 2 NS dns2.rr.com.
rr.com. 2 NS dns3.rr.com.
rr.com. 2 NS dns1.rr.com.
Authority
The response has no authority records.
Additional
dns1.rr.com. 2 A 69.134.7.5
dns2.rr.com. 2 A 69.134.147.5
dns3.rr.com. 2 A 69.134.7.6
dns5.rr.com. 2 A 69.134.7.7
dns6.rr.com. 2 A 76.85.228.83
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0