Apex domains cannot have CNAME records.
Question and response
Question
dig tolna.net. NS
Answer
tolna.net. 5 NS ns3.tolna.net.
tolna.net. 5 NS ns.tolna.net.
tolna.net. 5 NS ns.microsystem.hu.
tolna.net. 5 NS ns.is.hu.
tolna.net. 5 NS ns6.tolna.net.
Authority
The response has no authority records.
Additional
ns.tolna.net. 5 A 91.146.167.221
ns.microsystem.hu. 5 A 195.184.4.1
ns3.tolna.net. 5 A 91.146.167.221
ns6.tolna.net. 5 A 77.111.128.69
ns.tolna.net. 5 AAAA 2a01:5d0:0:2:0:0:0:3
ns3.tolna.net. 5 AAAA 2a01:5d0:0:2:0:0:0:3
ns6.tolna.net. 5 AAAA 2a01:5d0:0:3:0:0:0:3
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0