Insert data with PHP SQL MVC

I'm new on MVC method, I'm trying to add a new user to the database from a form, but after filling and submiting the form, it is not working; all I have is just a blank page.

the model.php

 // Add user form 
  public function addNewUser($rank,$type,$subtype,$email,$password,$lastname,$firstname,$phone,$country,$city,$adress,$company,$gender,$birth_date) {
       $db = $this->dbConenct();
       $req = $db->prepare('INSERT INTO crm_users(rank,type,subtype,email,password,lastname,firstname,phone,country,city,adress,company,gender,birth_date,reg_date)
        VALUES(?,?,?,?,?,?,?,?,?,?,?,?,?,?,NOW())');
       $addNewUser = $req->execute(array($rank,$type,$subtype,$email,$password,$lastname,$firstname,$phone,$country,$city,$adress,$company,$gender,$birth_date));

       return $addNewUser;
 } 

the controler.php

// Add a new user
function newUser($rank,$type,$subtype,$email,$password,$lastname,$firstname,$phone,$country,$city,$adress,$company,$gender,$birth_date) {
     $usersManager = new UsersManager();

   $addNewUser = $usersManager->addNewUser($rank,$type,$subtype,$email,$password,$lastname,$firstname,$phone,$country,$city,$adress,$company,$gender,$birth_date);
   // header('Location: ?content=users');
}

the router.php

newUser($_POST['rank'],$_POST['type'],$_POST['subtype'],$_POST['email'],$_POST['password'],$_POST['lastname'],$_POST['firstname'],$_POST['phone'],$_POST['country'],$_POST['city'],$_POST['adress'],$_POST['company'],$_POST['gender'],$_POST['birth_date']);

and the view.php

<form action="?content=users&action=addNewUser" method="POST" id="addUserForm">

<input type="text" name="lastname" placeholder="Nom..." required>   
<input type="text" name="firstname" placeholder="Prénom..." required>
<input type="date" name="birth_date" placeholder="Date de naissance...">
<input type="hidden" name="password" value="test">
<input type="text" name="company" placeholder="Entreprise...">


<select name="country" required>
  <option value="" disabled selected>Pays</option>
  <option value="Algeria">Algeria</option>
</select>

<input type="text" name="city" placeholder="Ville...">

<input type="text" name="adress" placeholder="Adresse...">

<input type="radio" name="gender" value="Homme">
<input type="radio" name="gender" value="Femme">

<select name="rank" required>
  <option value="" disabled selected>Rang</option>
  <option value="2">Administrateur</option>
  <option value="1">Utilisateur</option>
</select>   

<select name="type" required>
   <option value="" disabled selected>Type</option>
   <option value="Cominvolt">Cominvolt</option>
</select>   

<select name="subtype" required>
   <option value="" disabled selected>Sous-type</option>
   <option value="Développement">Développement</option>
</select>       
<input type="email" name="email" placeholder="E-mail..." required> 
<input type="tel" name="phone" placeholder="Numéro de téléphone..." required>
<button type="submit">AJOUTER</button>
</form>

Thank you very much for your time and help.