DeleteView lead to error 405 when submit is clicked on django

I have this small blog post app where everything works fine apart from delete view. As soon as I hit delete button I'm moved to my delete post page but when I hit confirm from DeleteView html page I get 405 error

My views.py for delete looks like this:

class DeletePost(DetailView):
    model = Articles
    template_name = 'delete_article.html'
    success_url = reverse_lazy('list_articles')

My html file where the link is mentioned is like this:

<!DOCTYPE html>
{% extends 'base.html' %}

{% block body %}
<div class="container">
{% for i in articles %}
    <div class="jumbotron">
        <h2>{{i.title}}</h2>
        <p>- {{i.author}}</p>
        {{i.created_on}}
        {{i.updated_on}}
        <p>{{i.content}}</p>
        <a class="btn btn-warning" href="{% url 'update_article' i.id %}">Update</a>
        <a class="btn btn-danger" href="{% url 'delete_article' i.id %}">Delete</a>
    </div>
{% endfor %}
</div>
{% endblock %}   

urls.py looks this way:

from django.urls import path

from mysite import views

urlpatterns = [
    path('articles/', views.PostList.as_view(), name='list_articles'),
    path('articles/<pk>/', views.PostDetail.as_view(), name='detail_article'),
    path('create/new/', views.CreateNewPost.as_view(), name='create_new_article'),
    path('update/<pk>/', views.UpdatePost.as_view(), name='update_article'),
    path('delete/<pk>/', views.DeletePost.as_view(), name='delete_article'),
]

and html for DeleteView:

<!DOCTYPE html>
{% extends 'base.html' %}

{% block body %}
<form method="post">
    {% csrf_token %}
    <p>Are you sure you want to delete "{{ object }}"?</p>
    {{ form.as_p }}
    <input class='btn btn-danger' type="submit"  value="Confirm">
</form>
{% endblock %}