Apex domains cannot have CNAME records.
Question and response
Question
dig unibuc.ro. NS
Answer
unibuc.ro. 5 NS ns2.unibuc.ro.
unibuc.ro. 5 NS ns5.unibuc.ro.
unibuc.ro. 5 NS ns1.unibuc.ro.
unibuc.ro. 5 NS ns3.unibuc.ro.
unibuc.ro. 5 NS ns4.unibuc.ro.
Authority
The response has no authority records.
Additional
ns1.unibuc.ro. 5 A 80.96.21.209
ns2.unibuc.ro. 5 A 80.96.21.76
ns3.unibuc.ro. 5 A 80.96.21.78
ns4.unibuc.ro. 5 A 193.226.52.4
ns5.unibuc.ro. 5 A 193.226.52.5
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0