The Port field on the LDAP Authentication configuration is not used when LDAP host is in LDAP URI format, this is, adding ldap:// or ldaps:// to the ip or hostname. Using this format, a custom ldap port must be specified in the URI. Like ldaps://hostname:3269. If not specified, the default ports are 389 for ldap:// and 636 for ldaps://.

This is the behavior of the ldap_connect php function, which is used by Zabbix: http://php.net/manual/en/function.ldap-connect.php

Please, add this information to the LDAP Authentication section in the Zabbix documentation.

Thank you very much.