Django - Изменения UpdateView не сохраняются, не используется success_url

I think I have a pretty basic UpdateView but the object is not saved when I submit the form. The success_url is never called. When I click the Update button, the form refreshes and I stay on the same page. I am able to update the object via admin, so I believe the model is working fine. I am not getting any errors.

урлы

path('classroomdetail/<uuid:classroom_id>/',
         views.classroomdetail, name='classroomdetail'),
         
path('classedit/<uuid:pk>/', views.ClassroomUpdateView.as_view(), name='classupdate'),

Модель

class Classroom(models.Model):
    id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
    user = models.ForeignKey(settings.AUTH_USER_MODEL,
                             on_delete=models.CASCADE)
    classroom_name = models.CharField(max_length=20)
    course = models.ForeignKey(Course, on_delete=models.CASCADE)
    students = models.ManyToManyField(Student)

    class Meta:
        constraints = [models.UniqueConstraint(
            fields=['user', 'classroom_name'], name="unique-user-classroom")]

    def __str__(self):
        return self.classroom_name

просмотров

class ClassroomUpdateView(UpdateView):
    model = Classroom
    fields = ['classroom_name']
    template_name_suffix = '_update'

    success_url = reverse_lazy('gradebook:classroom')

шаблон

{% extends 'base.html' %} {% load static %} {% block content %}
{% load crispy_forms_tags %}
<div class="container">
  <div class="row">
    <div class="col">
      <h3>This Classroom belongs to {{ classroom.course }}</h3>
    </div>
  </div>

  <div class="row">
    <div class="col-md-3">
      <form class="form-group">
        {% csrf_token %}{{ form|crispy }}
          <input type="submit" class="btn btn-primary mt-2 mb-2" value="Update">
      </form>
    </div>
  </div>
    <div class="row">
      <div class="col-md-3">
        <a href="{% url 'gradebook:classroomdetail' object.pk %}"><div class="ps-2">Cancel</a>
      </div>
    </div>
</div>
{% endblock content %}

<form method="post" class="form-group">