Apex domains cannot have CNAME records.
Question and response
Question
dig umbler.in. NS
Answer
umbler.in. 5 NS ns-678.awsdns-20.net.
umbler.in. 5 NS ns-1562.awsdns-03.co.uk.
umbler.in. 5 NS ns-295.awsdns-36.com.
umbler.in. 5 NS ns-1144.awsdns-15.org.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0