Apex domains cannot have CNAME records.
Question and response
Question
dig krypt.com. NS
Answer
krypt.com. 3 NS ns2.cf.krypt.com.
krypt.com. 3 NS ns3.cf.krypt.com.
krypt.com. 3 NS ns1.cf.krypt.com.
Authority
The response has no authority records.
Additional
ns1.cf.krypt.com. 3 A 162.159.8.96
ns2.cf.krypt.com. 3 A 162.159.9.147
ns3.cf.krypt.com. 3 A 162.159.10.155
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0