Apex domains cannot have CNAME records.
Question and response
Question
dig s1networks.fi. NS
Answer
s1networks.fi. 3 NS ns3.s1networks.fi.
s1networks.fi. 3 NS ns4.s1networks.fi.
s1networks.fi. 3 NS ns1.s1networks.fi.
s1networks.fi. 3 NS ns2.s1networks.fi.
Authority
The response has no authority records.
Additional
ns1.s1networks.fi. 3 A 185.11.208.10
ns2.s1networks.fi. 3 A 185.11.211.10
ns3.s1networks.fi. 3 A 35.234.125.120
ns4.s1networks.fi. 3 A 35.228.172.227
ns1.s1networks.fi. 4 AAAA 2a03:6f40:0:1:a800:1ff:febd:8fcf
ns2.s1networks.fi. 4 AAAA 2a03:6f40:0:2:a800:1ff:fe41:107c
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0