I configured server proxy (192.168.52.194) and I get errors:
Unable to connect to the server [Server_IP]:10051 [ cannot connect to [[ Server_IP]: 10051]: [4] Interrupted system call]
cannot send list of active checks to "192.168.53.125" : host [host_computer] not found
hostname on Zabbix GUI == hostname on agent

Proxy configuration:
Server=Server_IP
Hostname=Zabbix_proxy01
ConfigFrequency=60
Agent's configuration:
EnableRemoteCommands=0
Server=192.168.52.194
ServerActive=192.168.52.194
ListenPort=10050
Hostname=host_computer
Logs on agent:
22488:20190228:112046.331 no active checks on server [192.168.52.194:10051]: host [host_computer] not found
Proxy in active mode.
telnet from proxy to Server_IP 10050 is ok
Unable to connect to the server [Server_IP]:10051 [ cannot connect to [[ Server_IP]: 10051]: [4] Interrupted system call]
cannot send list of active checks to "192.168.53.125" : host [host_computer] not found
hostname on Zabbix GUI == hostname on agent
Proxy configuration:
Server=Server_IP
Hostname=Zabbix_proxy01
ConfigFrequency=60
Agent's configuration:
EnableRemoteCommands=0
Server=192.168.52.194
ServerActive=192.168.52.194
ListenPort=10050
Hostname=host_computer
Logs on agent:
22488:20190228:112046.331 no active checks on server [192.168.52.194:10051]: host [host_computer] not found
Proxy in active mode.
telnet from proxy to Server_IP 10050 is ok