Apex domains cannot have CNAME records.
Question and response
Question
dig gslb.srv.bnpparibas. NS
Answer
gslb.srv.bnpparibas. 5 NS presidcc1b.domivesta.net.
gslb.srv.bnpparibas. 5 NS presidcc2a.domivesta.net.
gslb.srv.bnpparibas. 5 NS presidcc2b.domivesta.net.
gslb.srv.bnpparibas. 5 NS presidcc1a.domivesta.net.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0