I cant register/add new user in my project when i added a domain , but it is working on localhost

I cant register/add new user in my project when i added a domain , but it is working when im only using xampp/localhost. there is a connection because i can login using an admin user and all the user that already registered in my database before i import it on 000webhost database and there is a connection because im able to login so im thinking that theres something i should change with my registration code. Please help im only a beginner

this is my code:

<?php
if(isset($_POST['submit'])){
$username = $_POST['username'];
$firstname = $_POST['firstname'];
$lastname = $_POST['lastname'];
$address = $_POST['address'];
$phone = $_POST['phone'];
$email = $_POST['email'];
$password = $_POST['password'];

if(!empty($username) && !empty($email) && !empty($password)){
    $username = mysqli_real_escape_string($connection,$username);
    $firstname = mysqli_real_escape_string($connection,$firstname);
    $lastname = mysqli_real_escape_string($connection,$lastname);
    $address = mysqli_real_escape_string($connection,$address);
    $phone = mysqli_real_escape_string($connection,$phone);
    $email = mysqli_real_escape_string($connection,$email);
    $password = mysqli_real_escape_string($connection,$password);

    $password = password_hash($password, PASSWORD_BCRYPT, array('cost' => 12)); 

    // $query = "INSERT INTO users (user_role,username,user_firstname,user_lastname,user_email,user_password) ";
    // $query .= "VALUES( 'subscriber','{$username}','{$firstname}','{$lastname}','{$email}','{$password}' )";
    // $register_user_query = mysqli_query($connection,$query);
    // if(!$register_user_query){
    //     die("QUERY FAILED" . mysqli_error($connection) . ' ' . mysqli_errno($connection));
    // }

    $query = "INSERT INTO users (user_role,username,user_firstname,user_lastname,user_address,user_phone,user_email,user_password) ";
    $query .= "VALUES( 'subscriber',?,?,?,?,?,?,?)";
    $stmt = mysqli_prepare($connection,$query);
    mysqli_stmt_bind_param($stmt,"sssssss",$username,$firstname,$lastname,$address,$phone,$email,$password);
    mysqli_stmt_execute($stmt);
    mysqli_stmt_close($stmt);
    if(!$stmt){
        die("QUERY FAILED" . mysqli_error($connection) . ' ' . mysqli_errno($connection));
    }

    $message = "Your Registration is successful";

}else{
    $message = "fields cannot be empty";
}

}else{
$message = ""; } ?>

this is my login code:

<?php include "db.php"; ?>
<?php session_start(); ?>
<?php
if(isset($_POST['login'])){
    $username = $_POST['username'];
    $password = $_POST['password'];
    $username = mysqli_real_escape_string($connection,$username);
    $password = mysqli_real_escape_string($connection,$password);
    $query = "SELECT * FROM users WHERE username = '{$username}' ";
    $login_user_query = mysqli_query($connection,$query);
    if(!$login_user_query){
        die("QUERY FAILED " . mysqli_error($connection)); 
    }
    while($row = mysqli_fetch_assoc($login_user_query)){
        $db_user_id = $row['user_id'];
        $db_username = $row['username'];
        $db_user_firstname = $row['user_firstname'];
        $db_user_lastname = $row['user_lastname'];
        $db_user_password = $row['user_password'];
        $db_user_role = $row['user_role']; }
        if(password_verify($password,$db_user_password)){
            $_SESSION['username'] = $db_username;
            $_SESSION['user_firstname'] = $db_user_firstname;
            $_SESSION['user_lastname'] = $db_user_lastname;
            $_SESSION['user_role'] = $db_user_role;
            // header("location: ../admin");
            header("location: userverify.php");
        } else{
            header("location: ../index.php");
        } 
    } 
    ?>

-- Table structure for table users

CREATE TABLE `users` (


`user_id` int(3) NOT NULL,
`username` varchar(255) NOT NULL,
`user_password` varchar(255) NOT NULL,
`user_firstname` varchar(255) NOT NULL,
`user_lastname` varchar(255) NOT NULL,
`user_address` varchar(255) NOT NULL,
`user_phone` varchar(255) NOT NULL,
`user_email` varchar(255) NOT NULL,
`user_image` text NOT NULL,
`user_role` varchar(255) NOT NULL,
`randSalt` varchar(255) NOT NULL DEFAULT 'blahblahblahh',
`token` text NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=latin1;

-- -- Dumping data for table users

INSERT INTO `users` (`user_id`, `username`, `user_password`, `user_firstname`, `user_lastname`, `user_address`, `user_phone`, `user_email`, `user_image`, `user_role`, `randSalt`, `token`)