if user is not None:
        login(request, user)  
        return redirect('home')  
    else:
        error_message = "Invalid username or password."
        return render(request, 'login.html', {'error_message': error_message})

Using the above code, if user enters wrong credentials, login.html shows up successfully with error message.

But now the URL is http://localhost:8000/authentication_view/.

Now if the user re-enters credentials, the URL will be
http://localhost:8000/authentication_view/authentication_view/,
and it creates Page Not Found error.

If I use return redirect('login_view'), then the error message will not show.

Could someone help me how to show login page with error message without adding Authentication View to the URL?

I was expecting: if user provides wrong credentials, he gets error message and goes back to login page. Now he can re-enter credentials. But now login page is not usable because authentication view name is already added to the URL. New login attempt will add authentication view name twice the URL.