Apex domains cannot have CNAME records.
Question and response
Question
dig sveit.is. NS
Answer
sveit.is. 5 NS ns02.office.is.
sveit.is. 5 NS ns01.office.is.
sveit.is. 5 NS ns03.office.is.
Authority
The response has no authority records.
Additional
ns01.office.is. 5 A 185.67.84.102
ns02.office.is. 5 A 185.67.84.111
ns03.office.is. 5 A 185.67.84.116
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0