I have this code here. The connection with the DB is okay, and when the variables’ values are strings, the values are inserted without any problem. However, when I’m using $_POST, the database inserts a new user with empty values and doesn’t take the values I inserted through the request.
note: I’m learning PHP from a few days.

this is the code:

    <?php

include "../connect.php";

$username=isset($_POST["username"]) ? $_POST["username"]:'';
$email=isset($_POST['email']) ? $_POST['email']:'' ;
$password=isset($_POST['password']) ? $_POST['password']:'';


$stm=$con->prepare("INSERT INTO `users` (`username`,`email`,`password`) VALUES 
(?,?,?)");
$stm->execute(params: array($username,$email,$password));
$count=$stm->rowCount();

if($count>0){
    echo json_encode(array('status'=>'sucsses'));
}else{
    echo json_encode(array('status'=>'fail'));
}

I use Thunder Client to send a request: