I want to let user re-order/sort table of content with drag and drop. And whene I push "Submit order" button (after re-order) I have error: ValidationError at /save-group-ordering/ ['“” is not a valid UUID.'] Request Method: POST Request URL: http://127.0.0.1:8000/save-group-ordering/ Django Version: 3.0.2 Exception Type: ValidationError Exception Value: ['“” is not a valid UUID.'] Traceback Switch to copy-and-paste view C:\Users\Admin.2\Desktop\taskmanager\ENV\lib\site- packages\django\db\models\fields\__init__.py in to_python return uuid.UUID(**{input_form: value}) … ▶ Local vars C:\Python 3.7\lib\uuid.py in __init__ raise ValueError('badly formed hexadecimal UUID string') … ▶ Local vars During handling of the above exception (badly formed hexadecimal UUID string), another exception occurred: C:\Users\Admin.2\Desktop\taskmanager\ENV\lib\site-packages\django\core\handlers\exception.py in inner response = get_response(request) … ▶ Local vars C:\Users\Admin.2\Desktop\taskmanager\ENV\lib\site-packages\django\core\handlers\base.py in _get_response response = self.process_exception_by_middleware(e, request) … ▶ Local vars C:\Users\Admin.2\Desktop\taskmanager\ENV\lib\site- packages\django\core\handlers\base.py in _get_response response = wrapped_callback(request, *callback_args, **callback_kwargs) … ▶ Local vars C:\Users\Admin.2\Desktop\taskmanager\ENV\lib\site-packages\django\views\decorators\http.py in inner return func(request, *args, **kwargs) … ▶ Local vars C:\Users\Admin.2\Desktop\taskmanager\tasks\views.py in save_new_ordering group = Task.objects.get(lookup_id__exact=lookup_id) … ▶ Local vars C:\Users\Admin.2\Desktop\taskmanager\ENV\lib\site-packages\django\db\models\manager.py in manager_method return getattr(self.get_queryset(), name)(*args, **kwargs) … ▶ Local vars C:\Users\Admin.2\Desktop\taskmanager\ENV\lib\site-packages\django\db\models\query.py in get clone = self._chain() if self.query.combinator else self.filter(*args, **kwargs) … ▶ Local vars C:\Users\Admin.2\Desktop\taskmanager\ENV\lib\site-packages\django\db\models\query.py in filter return self._filter_or_exclude(False, *args, **kwargs) … ▶ Local vars C:\Users\Admin.2\Desktop\taskmanager\ENV\lib\site-packages\django\db\models\query.py in _filter_or_exclude clone.query.add_q(Q(*args, **kwargs)) … ▶ Local vars C:\Users\Admin.2\Desktop\taskmanager\ENV\lib\site-packages\django\db\models\sql\query.py in add_q clause, _ = self._add_q(q_object, self.used_aliases) … ▶ Local vars C:\Users\Admin.2\Desktop\taskmanager\ENV\lib\site-packages\django\db\models\sql\query.py in _add_q check_filterable=check_filterable, … ▶ Local vars C:\Users\Admin.2\Desktop\taskmanager\ENV\lib\site-packages\django\db\models\sql\query.py in build_filter condition = self.build_lookup(lookups, col, value) … ▶ Local vars C:\Users\Admin.2\Desktop\taskmanager\ENV\lib\site-packages\django\db\models\sql\query.py in build_lookup lookup = lookup_class(lhs, rhs) … ▶ Local vars C:\Users\Admin.2\Desktop\taskmanager\ENV\lib\site- packages\django\db\models\lookups.py in init self.rhs = self.get_prep_lookup() … ▶ Local vars C:\Users\Admin.2\Desktop\taskmanager\ENV\lib\site-packages\django\db\models\lookups.py in get_prep_lookup return self.lhs.output_field.get_prep_value(self.rhs) … ▶ Local vars C:\Users\Admin.2\Desktop\taskmanager\ENV\lib\site-packages\django\db\models\fields_init_.py in get_prep_value return self.to_python(value) … ▶ Local vars C:\Users\Admin.2\Desktop\taskmanager\ENV\lib\site-packages\django\db\models\fields_init_.py in to_python params={'value': value}, … ▶ Local vars I only start work with django and I not understand what I am doing wrong. Here is my models.py class Task(models.Model): project = models.ForeignKey(Project, null=True, on_delete=models.CASCADE) title = models.CharField(max_length=300, null=True) complete = models.BooleanField(default=False) deadline = models.DateField('Deadline of the task (year, month, day)', default=date.today) created = models.DateTimeField(auto_now_add=True,null=True) lookup_id = models.UUIDField(default=uuid.uuid4, editable=False, db_index=True) order = models.IntegerField(blank=False, default=100_000) def __str__(self): return self.title def deadline_func(self): days = self.deadline - date.today() return days Here is my urls.py from django.urls import path from . import views urlpatterns = [ path('' , views.projects_list, name="list"), path('create_project/' , views.createProject, name="create_project"), path('deadline_project/<strk>' , views.deadlineProject, name="deadline_project"), path('update_project/<strk>' , views.updateProject, name="update_project"), path('delete_project/<strk>' , views.deleteProject, name="delete_project"), path('create_task/<strk>' , views.createTask, name="create_task"), path('save-group-ordering/', views.save_new_ordering, name='save-group-oldering'), path('deadline_task/<strk>' , views.deadlineTask, name="deadline_task"), path('update_task/<strk>' , views.updateTask, name="update_task"), path('delete_task/<strk>' , views.deleteTask, name="delete_task"), ] Here is my views.py @require_POST def save_new_ordering(request): form = OrderingForm(request.POST) if form.is_valid(): ordered_ids = form.cleaned_data["ordering"].split(',') with transaction.atomic(): current_order = 1 for lookup_id in ordered_ids: group = Task.objects.get(lookup_id__exact=lookup_id) group.order = current_order group.save() current_order += 1 return redirect('/') Here is my forms.py class TaskForm(forms.ModelForm): class Meta: model = Task fields = '__all__' class OrderingForm(forms.Form): ordering = forms.CharField() Here is my html <table class="raz"> <tbody id="groups"> {% for task in project.task_set.all %} <tr data-lookup="{{ folder.lookup_id }}"> <td style="width: 50px;"><span class="handle"><img src=" static/images/Up_Down.png " alt="Up_Down_icon"></span></td> {% if task.complete == True %} <td style="width: 50px;"class="ch"><input class="checkbox" type="checkbox" name="complete" id="id_complete" checked ></td> {% else %} <td style="width: 50px;"><input class="checkbox" type="checkbox" name="complete" id="id_complete" ></td> {% endif %} <td style="width: 550px;"><p>{{task.title}}</p></td> <td style="width: 50px;"><a class="calendar" href="{% url 'deadline_task' task.id %}"> <img src=" static/images/calendar.png " alt="calendar_icon"> </a></td> <td style="width: 50px;"><a href="{% url 'update_task' task.id %}" class="edittask"> <img src=" static/images/pencil_icon.png " alt="pencil_icon"> </a></td> <td style="width: 50px;"><a href="{% url 'delete_task' task.id %}" class="deletetask"> <img src=" static/images/trash.png " alt="trash_icon"> </a></td> </tr> {% endfor%} </tbody> </table> <form id="orderingForm" method="post" action="{% url 'save-group-oldering' %}"> {% csrf_token %} <input type="hidden" id="orderingInput" name="ordering"> </form> <button id="saveOrdering">Save ordering</button> Continue reading...