Страница не перенаправляется после нажатия на кнопку submit

Я сделал форму для отправки электронных писем с моего сайта. На нажатие кнопки submit, она должна перенаправляться на success страницу, но вместо этого получаю вот это:

Как я могу перенаправить пользователя на другую страницу?

скрипт, отвечающий за форму validate.js

* PHP Email Form Validation - v3.6
* URL: https://bootstrapmade.com/php-email-form/
* Author: BootstrapMade.com
*/
(function () {
  "use strict";

  let forms = document.querySelectorAll('.php-email-form');

  forms.forEach( function(e) {
    e.addEventListener('submit', function(event) {
      event.preventDefault();

      let thisForm = this;

      let action = thisForm.getAttribute('action');
      let recaptcha = thisForm.getAttribute('data-recaptcha-site-key');
      
      if( ! action ) {
        displayError(thisForm, 'The form action property is not set!');
        return;
      }
      thisForm.querySelector('.loading').classList.add('d-block');
      thisForm.querySelector('.error-message').classList.remove('d-block');
      thisForm.querySelector('.sent-message').classList.remove('d-block');

      let formData = new FormData( thisForm );

      if ( recaptcha ) {
        if(typeof grecaptcha !== "undefined" ) {
          grecaptcha.ready(function() {
            try {
              grecaptcha.execute(recaptcha, {action: 'php_email_form_submit'})
              .then(token => {
                formData.set('recaptcha-response', token);
                php_email_form_submit(thisForm, action, formData);
              })
            } catch(error) {
              displayError(thisForm, error);
            }
          });
        } else {
          displayError(thisForm, 'The reCaptcha javascript API url is not loaded!')
        }
      } else {
        php_email_form_submit(thisForm, action, formData);
      }
    });
  });

  function php_email_form_submit(thisForm, action, formData) {
    fetch(action, {
      method: 'POST',
      body: formData,
      headers: {'X-Requested-With': 'XMLHttpRequest'}
    })
    .then(response => {
      if( response.ok ) {
        return response.text();
      } else {
        throw new Error(`${response.status} ${response.statusText} ${response.url}`); 
      }
    })
    .then(data => {
      thisForm.querySelector('.loading').classList.remove('d-block');
      if (data.trim() == 'OK') {
        thisForm.querySelector('.sent-message').classList.add('d-block');
        thisForm.reset(); 
      } else {
        throw new Error(data ? data : 'Form submission failed and no error message returned from: ' + action); 
      }
    })
    .catch((error) => {
      displayError(thisForm, error);
    });
  }

  function displayError(thisForm, error) {
    thisForm.querySelector('.loading').classList.remove('d-block');
    thisForm.querySelector('.error-message').innerHTML = error;
    thisForm.querySelector('.error-message').classList.add('d-block');
  }

})();

views.py:

    #send_mail(subject, message, from_email, recipient_list)
    if request.method == 'POST':
        name = request.POST.get("name")
        email = request.POST.get("email")
        subject = request.POST.get("subject")
        message = request.POST.get('message')

        message_con = 'message:' + message+ ' \n email: '+email + '\n name of the sender:' + name
        send_mail(subject, message_con,settings.EMAIL_HOST_USER, ['aydyntour@gmail.com', 'khqyop@gmail.com'])
    
        return HttpResponseRedirect('core:success')

urls.py:

urlpatterns = [
    path("", views.index, name = "index"),
    path("blog", views.blog, name = "blog"),
    path('email/$', views.email, name = 'email'),
    path("blog-single", views.blogSingle, name = "blogSingle"),
    path("portfolio-details", views.portfolioDetails, name = "portfolioDetails"),
    path('add-form', views.addForm, name = "form"),
    path('success', views.success, name = 'success')
]

HTML форма:

          <div class="col-lg-6 mt-5 mt-lg-0" data-aos="fade-left" data-aos-delay="100" id = "#contactForm">
            <form action="{% url 'core:email' %}" method="post" role="form" class="php-email-form" >
              {% csrf_token %}
              <div class="row">
                <div class="col-md-6 form-group">
                  <input type="text" name="name" class="form-control" id="name" placeholder="Your Name" required>
                </div>
                <div class="col-md-6 form-group mt-3 mt-md-0">
                  <input type="email" class="form-control" name="email" id="email" placeholder="Your Email" required>
                </div>
              </div>
              <div class="form-group mt-3">
                <input type="text" class="form-control" name="subject" id="subject" placeholder="Subject" required>
              </div>
              <div class="form-group mt-3">
                <textarea class="form-control" name="message" rows="5" placeholder="Message" required></textarea>
              </div>
              <div class="my-3">
                <div class="loading">Loading</div>
                <div class="error-message"></div>
                <div class="sent-message">Your message has been sent. Thank you!</div>
              </div>
              <div class="text-center"><button type="submit">Send Message</button></div>
            </form>

          </div>

        </div>

      </div>
    </section><!-- End Contact Section -->