Steps to reproduce:

1. Configure DB encryption between backend and frontend
2. In pg_hba.conf set configuration to as in screenshot:
3. Zabbix server will start using encrypted connection as expected, but frontend will not be able to connect to the database:

Result:
Log file suggests that frontend uses unencrypted connection:

2024-01-23 14:33:35.886 254764 zabbix: FATAL:  no pg_hba.conf entry for host "**.***.***.**", user "********", database "zabbix", SSL off 

Frontend configuration:

$DB['ENCRYPTION'] = true;
$DB['KEY_FILE'] = '';
$DB['CERT_FILE'] = '';
$DB['CA_FILE'] = '/etc/ssl/pgsql/root.crt';
$DB['VERIFY_HOST'] = false;
$DB['CIPHER_LIST'] = ''; 

As soon as the pg_hba.conf set to:

Frontend is able to connect
Expected:
Frontend to use encrypted connections