My html code can not be seen because of a php line

Question

I am building a dynamic website and I am trying to do a prepared request but when ever I type execute command the browser cant load the HTML code below the PHP code.

Here is my code .

Before I have some html / php code

  <div class="lien">
                          <p>Date</p>
                          <input type="date" name="date">
                      </div>
                      <div class="titre">
                          <p>Information</p>
                          <input type="text" name="info">
                      </div>
                      <div class="submit">
                          <input type="submit" value="submit">
                      </div>
                      <input type="hidden" value="<?php echo $donnees['id'];?>" name="userid">
                      <?php

                        $date = isset( $_POST['date'] ) ? $_POST['date'] : "";
                        $matiere = isset( $_POST['matiere'] ) ? $_POST['matiere'] : "";
                        $classe = isset( $_POST['classe'] ) ? $_POST['classe'] : "";
                        $info = isset( $_POST['info'] ) ? $_POST['info'] : "";
                        $userid = $_SESSION['id'];

                        $requete = $bdd -> prepare('INSERT INTO calendrier (date , matiere , classe , titre , userid) VALUES (?,?,?,?,?)');
                        $requete -> execute(array($date , $matiere , $classe , $info , $userid ));
                      ?>
                  </div>
              </form>

          </div>
      </section>
      <section class="afficheCalendar" id="afficheCalendar">
          <div id="taskContenaire">
              <!--TASK-->
                <?php


                $req = $b

and here too

Whenever I remove $requete -> execute(array($date , $matiere , $classe , $info , $userid )); the website works normally.

Here is before (when the execute is in my code)

And here is after I delete the line