Apex domains cannot have CNAME records.
Question and response
Question
dig gsi-network.com. NS
Answer
gsi-network.com. 4 NS dns.gsi-network.com.
gsi-network.com. 4 NS sdns2.ovh.net.
Authority
The response has no authority records.
Additional
dns.gsi-network.com. 4 A 37.59.32.166
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0