Steps to reproduce:

1. Configure zabbix_agentd.conf with TLS using certificate, for example:
   • TLSConnect=cert
   • TLSAccept=cert
   • TLSCAFile=/path/zabbix_ca_file
   • TLSServerCertIssuer=CN=Signing CA,OU=development,O=Zabbix,DC=zabbix,DC=com
   • TLSServerCertSubject=CN=proxy,OU=development,O=Zabbix,DC=zabbix,DC=com
   • TLSCertFile=/path/zabbix_agentd.crt
   • TLSKeyFile=/path/zabbix_agentd.key
2. Configure host in frontend with TLS, Certificate.
3. Run server and agent.

Result:
Agent does not notice that server certificate has the issuer and subject other than required by agent configuration (validation is broken).

Expected:
Agent refuses to talk to server which has other certificate issuer/subject than configured in zabbix_agentd.conf.