Apex domains cannot have CNAME records.
Question and response
Question
dig uranus.fi. NS
Answer
uranus.fi. 5 NS ns3.laura.fi.
uranus.fi. 5 NS ns2.laura.fi.
uranus.fi. 5 NS ns1.laura.fi.
Authority
The response has no authority records.
Additional
ns1.laura.fi. 5 A 95.175.113.180
ns2.laura.fi. 5 A 95.175.113.185
ns3.laura.fi. 5 A 185.11.208.219
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0