Apex domains cannot have CNAME records.
Question and response
Question
dig calcucloudsvcs.com. NS
Answer
calcucloudsvcs.com. 5 NS ns1.calcucloudsvcs.com.
calcucloudsvcs.com. 5 NS ns2.calcucloudsvcs.com.
Authority
The response has no authority records.
Additional
ns1.calcucloudsvcs.com. 5 A 23.254.209.75
ns2.calcucloudsvcs.com. 5 A 108.174.194.134
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0