Apex domains cannot have CNAME records.
Question and response
Question
dig 2gis.com. NS
Answer
2gis.com. 2 NS ns.2gis.tech.
2gis.com. 2 NS ns2.2gis.com.
2gis.com. 2 NS ns3.2gis.com.
2gis.com. 2 NS ns.2gis.com.
Authority
The response has no authority records.
Additional
ns.2gis.com. 2 A 91.236.51.51
ns.2gis.tech. 2 A 95.174.68.40
ns.2gis.tech. 2 A 103.172.116.185
ns2.2gis.com. 2 A 91.236.50.7
ns2.2gis.com. 2 A 91.236.50.171
ns3.2gis.com. 2 A 31.40.218.252
ns3.2gis.com. 2 A 213.226.69.44
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0