Ajax chained dropdown not loading/working correctly on the LIVE server – PHP Versions

I have a country, state and city chained dropdown which loads a state depending on the country and loads the cities depending on the state. The code works perfectly fine on my local server but when pushing to the live one, the dropdown is not functioning correctly, for example in some cases it works fine for all 3 but for some cases it just does not load anything and in the console I am seeing a simple false and nothing else.

Here is the JS:

$(document).ready(function() {    
    var country_id = localStorage.getItem("select2CountryValue");
    var state_id = localStorage.getItem("select2StateValue");
    var page_load = true; //added this 

    // Triggering the deleteLocalStorage function in case the client is not 
    // created and the back button is clicked
    $('.del-ls').click(function() {
        deleteLocalStorage();
    });

    // This function is also called by PHP using script tags when the create
    // client form is successfully submitted
    function deleteLocalStorage() {
        var country_id = localStorage.getItem("select2CountryValue");
        var state_id = localStorage.getItem("select2StateValue");

        localStorage.removeItem('select2CountryValue');
        localStorage.removeItem('select2StateValue');
    }

    //$('.csc-select').select2(); 
    $('#country').select2({
        placeholder: 'Select Country'
    });

    $('#state').select2({
        placeholder: 'Select State/Region'
    });

    $('#city').select2({
        placeholder: 'Select City'
    });

    $('select[name="country"]').on('change',function() {
        var country_id= $(this).val();
        localStorage.setItem("select2CountryValue", country_id);
        if (country_id) {
            $.ajax({
                url: "/src/Pages/world/getStates.php",
                type: "GET",
                data: {'country_id':country_id},
                dataType: "json",
                success: function(data) {
                    console.log(data);
                    $('select[name="state"]').empty();
                    $('select[name="state"]').append('<option value="">Select State</option>');
                    $.each(JSON.parse(data), function(key,value) {
                        $('select[name="state"]').append('<option value="'+value.id+'">'+value.name+'</option>');
                    });
                    //check if the change is called on page load
                    if (page_load == true) {
                        $('#state').val(state_id).trigger('change'); //assign slected value after element option is added in dom
                        page_load = false; //adding this so that next time this doesn't get execute
                    }
                }
            });
        } else {
            $('select[name="state"]').empty();
       }
    });
    
    $('#country').val(country_id).trigger('change');

    $('select[name="state"]').on('change',function() {
        var country_id = $('#country').val();
        var state_id = $(this).val();
        localStorage.setItem("select2StateValue", state_id);
        if (state_id) {
            $.ajax({
                url: "/src/Pages/world/getCities.php",
                type: "GET",
                data: {'country_id': country_id, 'state_id': state_id},
                dataType: "json",
                success: function(data) {
                    console.log(data);
                    $('select[name="city"]').empty();
                    $('select[name="city"]').append('<option value="">Select City</option>');
                    $.each(JSON.parse(data),function(key,value) {
                        $('select[name="city"]').append('<option value="'+value.id+'">'+value.name+'</option>');
                    });
                }
            });
        } else {
            $('select[name="city"]').empty();
        }
    });
});

And this is the HTML and just a some simple PHP to load the countries which is working fine:

<p>
    <span>Country</span>
    <select class="csc-select" name="country" id="country">
        <option value="">Select Country</option>
        <?php foreach($countries as $country) { ?>
        <option value="<?php echo $country[$columnName['COLUMN_NAME']]; ?>"
        >
            <?php echo $country['name']; ?>
        </option>
        <?php } ?>
    </select>
</p>
<p>
    <span>State</span>
    <select class="csc-select" name="state" id="state">
        <option value="">Select State</option>
    </select>
</p>
<p>
    <span>City</span>
    <select class="csc-select" name="city" id="city">
        <option value="">Select City</option>
    </select>
</p>

I am a bit clueless now since locally it works perfectly however on the live server it doesn’t work for every option you pick, I rechecked the countries, states and cities database and all the info is there so its not missing, the database is identical to the one I am using in the local version too. If anyone has any idea or suggestions, I would appreciate it a lot.

And here is the console log error that appears sometimes:

> Uncaught SyntaxError: Unexpected end of JSON input
>     at JSON.parse (<anonymous>)
>     at Object.success (add:977:29)
>     at c (jquery-3.6.0.min.js:2:28327)
>     at Object.fireWith [as resolveWith] (jquery-3.6.0.min.js:2:29072)
>     at l (jquery-3.6.0.min.js:2:79901)
>     at XMLHttpRequest.<anonymous> (jquery-3.6.0.min.js:2:82355)

and now I am adding a screenshot of the console.log, this happens when I choose the country United States, the state Caliornia, so it does not show anything for California but it should:

Here is the getStates.php file code:

<?php 

use AppSession;
use AppLogin;
use AppLocation;

require_once("../../../vendor/autoload.php");

$objSession = new Session();
if(!$objSession->isLogged()) {
    Login::redirectTo("/login");
}

$country_id = $_GET['country_id'];

if(isset($_GET['country_id'])) {
    $objLocation = new Location();
    echo json_encode($getStates = $objLocation->getStates($country_id));
}

and here is the getCities.php file code:

<?php 

use AppSession;
use AppLogin;
use AppLocation;

require_once("../../../vendor/autoload.php");

$objSession = new Session();
if(!$objSession->isLogged()) {
    Login::redirectTo("/login");
}

$state_id = $_GET['state_id'];
$country_id = $_GET['country_id'];

if(isset($_GET['state_id']) && isset($_GET['country_id'])) {
    $objLocation = new Location();
    echo json_encode($getCities = $objLocation->getCities($state_id, $country_id));
}

and this is the code in the Location class that fetches the data:

public function getStates(string $id): ?string
    {

        $sql = "SELECT `id`, `name` FROM {$this->table_3}
                WHERE `country_id` = '". $this->escape($id) ."'
                ORDER BY `name` ASC";
                $result = $this->fetchAll($sql);
                return json_encode($result);

    }

    public function getCities(string $state, string $country): bool|string
    {

        $sql = "SELECT `id`, `name` FROM {$this->table_4}
                WHERE `state_id` = '". $this->escape($state) ."'
                AND `country_id` = '". $this->escape($country) ."'
                ORDER BY `name` ASC";
                $result = $this->fetchAll($sql);
                return json_encode($result);

    }