Apex domains cannot have CNAME records.
Question and response
Question
dig cOnNeCt.sPb.Ru. NS
Answer
connect.spb.ru. 5 NS ns1.connect.spb.ru.
connect.spb.ru. 5 NS ns2.connect.spb.ru.
Authority
The response has no authority records.
Additional
ns1.cOnNeCt.sPb.Ru. 5 A 188.134.6.132
ns2.cOnNeCt.sPb.Ru. 5 A 146.66.181.162
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0