Apex domains cannot have CNAME records.
Question and response
Question
dig riverwatcher.com. NS
Answer
riverwatcher.com. 5 NS yellow.soltec.net.
riverwatcher.com. 5 NS blue.soltec.net.
Authority
The response has no authority records.
Additional
blue.soltec.net. 5 A 68.70.162.70
yellow.soltec.net. 5 A 68.70.162.71
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0