Apex domains cannot have CNAME records.
Question and response
Question
dig 2gis.tech. NS
Answer
2gis.tech. 1 NS ns.2gis.com.
2gis.tech. 1 NS ns3.2gis.ru.
2gis.tech. 1 NS ns2.2gis.ru.
2gis.tech. 1 NS ns.2gis.tech.
Authority
The response has no authority records.
Additional
ns.2gis.com. 2 A 91.236.51.51
ns.2gis.tech. 3 A 95.174.68.40
ns.2gis.tech. 3 A 103.172.116.185
ns2.2gis.ru. 2 A 91.236.50.7
ns2.2gis.ru. 2 A 91.236.50.171
ns3.2gis.ru. 2 A 91.221.199.133
ns3.2gis.ru. 2 A 212.20.27.10
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0