Apex domains cannot have CNAME records.
Question and response
Question
dig integrys.it. NS
Answer
integrys.it. 5 NS ns1.dns4userver.com.
integrys.it. 5 NS ns3.dns4userver.com.
integrys.it. 5 NS ns2.dns4userver.com.
Authority
The response has no authority records.
Additional
ns1.dns4userver.com. 5 A 185.81.7.132
ns2.dns4userver.com. 5 A 93.95.222.132
ns3.dns4userver.com. 5 A 87.98.154.98
ns1.dns4userver.com. 5 AAAA 2a02:24b8:3:1784:0:0:0:0
ns3.dns4userver.com. 5 AAAA 2001:41d0:203:daac:0:0:0:4
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0