Apex domains cannot have CNAME records.
Question and response
Question
dig swiftapp.cloud. NS
Answer
swiftapp.cloud. 4 NS dns1.swiftrfp.net.
swiftapp.cloud. 4 NS dns2.swiftrfp.net.
Authority
The response has no authority records.
Additional
dns1.swiftrfp.net. 4 A 23.150.248.43
dns2.swiftrfp.net. 4 A 23.150.248.43
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0