Mysql does not log with Prepared Statement

Question

This code should redirect the user from the login page to the menu. However, after changing a simple query to a prepared statement, I can’t log in anymore, because $quant always returns empty. Some light?

<?php
session_start();
include 'config.php';
$con = conectar();

$usuario= $_POST['usuario'];
$senha= $_POST['senha'];

$sql = "SELECT * FROM adm WHERE usuario LIKE ? AND senha = ?";
$stmt= mysqli_prepare($con,$sql);

mysqli_stmt_bind_param($stmt, 'ss', $usuario, $senha);

mysqli_stmt_execute($stmt);
mysqli_stmt_store_result($stmt);

$reg = mysqli_stmt_fetch($stmt);
$quant = mysqli_stmt_num_rows($stmt);

mysqli_stmt_close($stmt);

if($quant!=0) {
    $_SESSION['codigo'] = $reg['cod_adm'];
    $_SESSION['usuario'] = $reg['usuario'];
    $_SESSION['senha'] = $reg['senha'];
    $_SESSION['tipo'] = 'adm';
    header('location:menu.php');
} 

else{
    $sql = "SELECT * FROM comum WHERE usuario LIKE ? AND senha = ?";
    $stmt = mysqli_prepare($con,$sql);

    mysqli_stmt_bind_param($stmt, 'ss', $usuario, $senha);

    mysqli_stmt_execute($stmt);
    mysqli_stmt_store_result($stmt);

    $reg = mysqli_stmt_fetch($stmt);
    $quant = (mysqli_stmt_num_rows($stmt));

    mysqli_stmt_close($stmt);

    if ($quant==0){
        echo "<center>
            <h2>
                <b>Login ou senha inválidos!</b>
            </h2>
        </center>";
        echo "<center>
            <a href='../home.html' class='voltar'>
                <span><b>Voltar</b></span>
            </a>
        </center>";
    }

    else {
        $_SESSION['codigo'] = $reg['cod_comum'];
        $_SESSION['usuario'] = $reg['usuario'];
        $_SESSION['senha'] = $reg['senha'];
        $_SESSION['tipo'] = 'comum';
        header('location:menu.php');
    } 
}?>