Apex domains cannot have CNAME records.
Question and response
Question
dig rockhoster.net. NS
Answer
rockhoster.net. 5 NS blue.rockhoster.in.
rockhoster.net. 5 NS red.rockhoster.in.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0