Apex domains cannot have CNAME records.
Question and response
Question
dig optron.lv. NS
Answer
optron.lv. 5 NS ns2.optron.lv.
optron.lv. 5 NS ns1.optron.lv.
Authority
The response has no authority records.
Additional
ns1.optron.lv. 5 A 217.28.48.38
ns2.optron.lv. 5 A 83.223.150.171
ns1.optron.lv. 5 AAAA 2a02:2880:3:2:0:0:0:a
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0