Curl return nothing php

Question

I try to access the output from curl with jquery ajax, but the result is empty not show any error. But when i try access to local server that working fine i dont know where the problem, i have research for 1 day but nothing result. can anyone help me that mean a lot for me

Here the jquery:

<script>
    $(document).ready(function() {

        $.support.cors = true;

        $("#login").on("click", function() {
            validation();
        })

        function validation() {

            let username = $("#username").val();
            let password = $("#password").val();

            getData();

        }

        function getData() {

            let username = $("#username").val();
            let password = $("#password").val();

            $.ajax({
                url: "<?= base_url('ajax') ?>",
                type: "GET",
                dataType: "text",
                data: {
                    username: username,
                    password: password
                },
                success: function(data) {
                    

                    console.log(data);

                }

            });

        }

    });
</script>

Here the curl

public function index()
{
    if (isset($_GET['username']) && isset($_GET['password'])) {
        $ch = curl_init();
        $username = $_GET['username'];
        $password = $_GET['password'];
        curl_setopt($ch, CURLOPT_URL, "http://" . $this->ip_library->ip_connection() . "/" . $this->ip_library->folder() . "/restapi.php?function=login&nis=" . $username . "&pass=" . $password);
        curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
        $output = curl_exec($ch);
        echo $output;
        curl_close($ch);

    }
    
}