Apex domains cannot have CNAME records.
Question and response
Question
dig customer.academica.fi. NS
Answer
customer.academica.fi. 5 NS ns2.vcloud.fi.
customer.academica.fi. 5 NS ns3.vcloud.fi.
customer.academica.fi. 5 NS ns1.vcloud.fi.
Authority
The response has no authority records.
Additional
ns1.vcloud.fi. 5 A 87.108.25.49
ns2.vcloud.fi. 5 A 82.133.128.49
ns3.vcloud.fi. 5 A 80.69.174.67
ns1.vcloud.fi. 5 AAAA 2001:a68:1:b:0:0:0:4
ns2.vcloud.fi. 5 AAAA 2001:a68:1:e:0:0:0:4
ns3.vcloud.fi. 5 AAAA 2a04:3540:1000:310:4bb:7cff:fe6d:826
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0