J'arrive pas à intégrer mes données dans ma base de donnée

<?php
  //connection au serveur
 $servername = "localhost";
$username = "root";
$password = "*****";
$dbname = "CPMC";

// Create connection
$conn = new mysqli($servername, $username, $password, $dbname);
// Check connection
if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
}

//récupération des valeurs des champs:
  //nom:
    $nom     = $_POST["Nom_pat"] ;
    //prenom:
    $prenom = $_POST["Prenom_pat"] ;
    $nom_jeune    = $_POST["Nom_jeune_fille"] ;
    $sexe=$_POST["Sexe_pat"];
    $naiss=$_POST["Dat_naiss"];
    echo '$naiss';
    $lieu=$_POST["Lieu_naiss"];
    //adresse:
    $adresse = $_POST["Adr_pat"] ;
    //numéro de téléphone:
    $tel = $_POST["Tel_pat"] ;
    //code postal:
    $mail = $_POST["Email_pat"] ;
    $group=$_POST["grp_sang"];

  //création de la requête SQL:
  $sql = "INSERT INTO Patient (Nom_pat, Prenom_pat, Nom_jeune_fille,Sexe_pat,Dat_naiss,Lieu_naiss,Adr_pat,Tel_pat,Email_pat,grp_sang)
         VALUES ('$nom ',' $prenom' ,'$nom_jeune ' ,'$sexe','$naiss','$lieu','$adresse ','$tel ','$mail','$group') " ;

  //exécution de la requête SQL:
$result = $conn->query($sql);
if ($conn->query($sql) === TRUE) {
    echo "New record created successfully";
} else {
    echo "Error: " . $sql . "<br>" . $conn->error;
}
?>

<form class="appointment-form" action= "insert_pat.php" method="POST">
                          <div class="row">
                            <div class="col-md-6 col-sm-6">
                              <label class="control-label">Nom patient <span class="required">*</span>
                              </label>
                              <input type="Nom patient" class="wp-form-control wpcf7-text" placeholder="Nom du patient" name="Nom_pat">
                            </div>
                            <div class="col-md-6 col-sm-6">
                              <label class="control-label">Prénom patient <span class="required">*</span>
                              </label>
                              <input type="Prenom patient" class="wp-form-control wpcf7-text" placeholder="Prenom patient" name="Prenom_pat">  
                            </div>
                          </div>
                          <div class="row">
                            <div class="col-md-6 col-sm-6">
                              <label class="control-label">Nom de jeune fille <span class="required">*</span>
                              </label>
                              <input type="text" class="wp-form-control wpcf7-text" placeholder="Nom de jeune fille" name="Nom_jeune_fille">
                            </div>
                            <div class="col-md-6 col-sm-6">
                              <label class="control-label">Sexe <span class="required">*</span>
                              </label>
                               <select class="wp-form-control wpcf7-select">
                                <option val="1">Femme</option>
                                <option val="2">Homme</option>
                              </select> 

                            </div>
                          </div>
                          <div class="row">
                            <div class="col-md-6 col-sm-6">
                              <label class="control-label">Date de naissance<span class="required">*</span>
                              </label>
                              <input type="text" class="wp-form-control wpcf7-text" placeholder="yy/mm/dd" name="Dat_naiss">
                            </div>
                            <div class="col-md-6 col-sm-6">
                              <label class="control-label">Lieu de naissance <span class="required">*</span>
                              </label>
                               <input type="text" class="wp-form-control wpcf7-text" placeholder="Lieu de naissance" name="Lieu_naiss">  
                            </div>
                          </div>
                          <div class="row">
                            <div class="col-md-6 col-sm-6">
                              <label class="control-label">Adresse patient<span class="required">*</span>
                              </label>
                              <input type="text" class="wp-form-control wpcf7-text" placeholder="adresse patient" name="Adr_pat">
                            </div>
                            <div class="col-md-6 col-sm-6">
                              <label class="control-label">Téléphone patient <span class="required">*</span>
                              </label>
                               <input type="text" class="wp-form-control wpcf7-text" placeholder="Téléphone patient" name="Tel_pat">  
                            </div>
                          </div>
                          <div class="row">
                            <div class="col-md-6 col-sm-6">
                              <label class="control-label">Email patient<span class="required">*</span>
                              </label>
                              <input type="mail" class="wp-form-control wpcf7-text" placeholder="Email patient" name="Email_pat">
                            </div>
                            <div class="col-md-6 col-sm-6">
                              <label class="control-label">groupe sanguin <span class="required">*</span>
                              </label>
                               <input type="text" class="wp-form-control wpcf7-text" placeholder="groupe sanguin" name="grp_sang">  
                            </div>
                          </div>

<button class="wpcf7-submit button--itzel " type="submit"><i class="button__icon fa fa-save"></i><span>Enregistrer</span></button>  
                        </form>