Apex domains cannot have CNAME records.
Question and response
Question
dig suburbanbroadband.net. NS
Answer
suburbanbroadband.net. 2 NS ns1.risebroadband.com.
suburbanbroadband.net. 2 NS ns2.risebroadband.com.
Authority
The response has no authority records.
Additional
ns1.risebroadband.com. 1 A 199.26.60.53
ns2.risebroadband.com. 1 A 199.26.61.9
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0