Problem when performing update

I have on the site the system to register, list and edit users.

Registering and Listing are ok, however, when trying to update a record, it does not change in DB and also does not return any errors. I already checked the connection and it's correct.

Here are the codes:

listar.php

<?php
include_once("conexao.php");

$result_usuario = "SELECT * FROM clientes";
$resultado_usuario = mysqli_query($conn, $result_usuario);
while ($row_usuario = mysqli_fetch_assoc($resultado_usuario)){
    echo $row_usuario['id_cli']."<br>";
    echo $row_usuario['nome_cli']."<br>";
    echo $row_usuario['cpf_cli']."<br>";
    echo $row_usuario['cnpj_cli']."<br>";
    echo $row_usuario['raz_cli']."<br>";
    echo $row_usuario['tel_cli']."<br>";
    echo $row_usuario['cel_cli']."<br>";
    echo $row_usuario['email_cli']."<br>";
    echo $row_usuario['senha_cli']."<br>";
    echo $row_usuario['nivel']."<br>";
    echo $row_usuario['ip_cli']."<br>";
    echo $row_usuario['data_cad_cli']."<br>"; ?>

<a href="editar.php?id=<?php echo $row_usuario['id_cli']; ?>">Editar</a>
<hr>

<?php }
?>

edit.php

    <?php
include_once("conexao.php");

$id = $_GET['id'];
$result_usuario = "SELECT * FROM clientes WHERE id_cli=$id";
$resultado_usuario = mysqli_query($conn, $result_usuario);
$row_usuario = mysqli_fetch_assoc($resultado_usuario);
?>

<form method="post" action="processa_edicao.php">
<input name="id_cli" type="number" readonly id="id" value="<?php echo $row_usuario['id_cli'] ?>">
<input name="nome_cli" type="text" required="required" id="nome" placeholder="Nome Completo" value="<?php echo $row_usuario['nome_cli'] ?>">
<input name="cpf_cli" type="number" required="required" id="cpf" placeholder="CPF" value="<?php echo $row_usuario['cpf_cli'] ?>">
<input name="cnpj_cli" type="number" id="cnpj" placeholder="CNPJ" value="<?php echo $row_usuario['cnpj_cli'] ?>">
<input name="raz_cli" type="text" id="razao_social" placeholder="Razão Social" value="<?php echo $row_usuario['raz_cli'] ?>">
<input name="tel_cli" type="tel" id="telefone" placeholder="(99)9999-9999" value="<?php echo $row_usuario['tel_cli'] ?>">
<input name="cel_cli" type="tel" id="celular" placeholder="(99)99999-9999" value="<?php echo $row_usuario['cel_cli'] ?>">
<input name="email_cli" type="email" required="required" id="email" placeholder="E-mail" value="<?php echo $row_usuario['email_cli'] ?>">
<input name="senha_cli" type="text" required="required" id="senha" placeholder="Senha" value="<?php echo $row_usuario['senha_cli'] ?>">
<select name="nivel" required id="nivel">
  <option value="1">Selecione</option>
  <option value="1">Básico</option>
  <option value="2">Profissional</option>

  <input name="ip_cli" type="number" readonly id="ip" value="<?php echo $row_usuario['ip_cli'] ?>">
  <input name="data_cad_cli" type="datetime" readonly id="data_cad" value="<?php echo $row_usuario['data_cad_cli'] ?>">

  <input type="submit" value="Editar">
</select>
</form>

processa_edicao.php

<?php
$nome = $_POST['nome_cli'];
$cpf = $_POST['cpf_cli'];
$cnpj = $_POST['cnpj_cli'];
$razao_social = $_POST['raz_cli'];
$telefone = $_POST['tel_cli'];
$celular = $_POST['cel_cli'];
$email = $_POST['email_cli'];
$senha = $_POST['senha_cli'];
$nivel_id = $_POST['nivel'];

$id = $_POST['id'];

include_once("conexao.php");

$result_usuario = "UPDATE clientes SET nome_cli = '$nome', cpf_cli = '$cpf', cnpj_cli = '$cnpj', raz_cli = '$razao_social', tel_cli = '$telefone', cel_cli = '$celular', email_cli = '$email', senha_cli = '$senha', nivel = '$nivel_id'  WHERE id_cli = '$id'";
$resultado_usuario = mysqli_query($conn, $result_usuario) or die(mysqli_error($conn));

header("location: listar.php");
?>

connection.php

<?php
$servidor = "localhost";
$usuario = "root";
$senha = "";
$dbname = "cadastro_usuarios";

//Criar a conexao
$conn = mysqli_connect($servidor, $usuario, $senha, $dbname);

if(!$conn){
    die("Falha na conexao: " . mysqli_connect_error());
}else{
    //echo "Conexao realizada com sucesso";
}
?>