通过查询字符串插入MySQL数据库[重复]

I'm trying to save data to my remote MySQL DB. I tested this script on Postman. But it gives this error {"error":true,"message":"Please try later"} I tried different insert into methods. But I take mostly 500 internal server error. How do I fix it?

<?php


define('DB_HOST','**.**.***.***');
define('DB_USERNAME','*******');
define('DB_PASSWORD','*******');
define('DB_NAME', '*******');

//Connecting to the database
$conn = new mysqli(DB_HOST, DB_USERNAME, DB_PASSWORD, DB_NAME);


if($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
}

$response = array();


if($_SERVER['REQUEST_METHOD']=='POST'){


    $emoji = $_POST['emoji'];
    $comment = $_POST['comment'];
    $date = $_POST['date'];

    $stmt = $conn->prepare("INSERT INTO datas (emoji, comment, date) VALUES (?, ?, ?)");

    $stmt->bind_param("sss", $emoji, $comment, $date);

    if($stmt->execute()){
        //making success response 
        $response['error'] = false;
        $response['message'] = 'Name saved successfully';
    }else{
        //if not making failure response 
        $response['error'] = true;
        $response['message'] = 'Please try later';
    }

}else{
    $response['error'] = true;
    $response['message'] = "Invalid request";
}


echo json_encode($response);

</div>