Apex domains cannot have CNAME records.
Question and response
Question
dig compute.prod-cloud-ocb.orange-business.com. NS
Answer
compute.prod-cloud-ocb.orange-business.com. 5 NS ns2.prod-cloud-ocb.orange-business.com.
compute.prod-cloud-ocb.orange-business.com. 5 NS ns1.prod-cloud-ocb.orange-business.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0