Account with this Email already exists. how to fix this?

I tried to create a login form. But when I try to login django gives the error that Account with this Email already exists. i don`t now how to fix this.Help me plz

Here is my code, please tell me where I'm going wrong:

forms.py

class AccountAuthenticationForm(forms.ModelForm):
    password = forms.CharField(label='Password', widget=forms.PasswordInput)

    class Meta:
        model= Account
        fields = ('email', 'password')

    def clen(self):
        email = self.cleaned_data['email']
        password = self.cleaned_data['password']
        if not authenticate(email=email, password=password):
            raise forms.ValidationError("Invalid login")

views.py

def login_view(request):
    
    context = {}

    user = request.user
    if user.is_authenticated:
        return redirect("home")

    if request.POST:
        form = AccountAuthenticationForm(request.POST)
        if form.is_valid():
            email=request.POST['email']
            password = request.POST['password']
            user =authenticate(email=email, password=password)

            if user:
                login(request,user)
                return redirect("home")
    else:
        form = AccountAuthenticationForm()

    context['login_form'] = form
    return render(request, 'account/login.html', context)

login.html

{% extends 'base.html' %}

{% block content %}

<h2>Login</h2>
<form method="post">{% csrf_token %}
    {% for field in login_form %}
        <p>
            {{field.label_tag}}
            {{field}}

            {% if field.help_text %}
                <small style="color:grey">{field.help_text}</small>
            {% endif %}


            {% for error in field.errors %}
                <p style="color:red">{{error}}</p>
            {% endfor %}


            {% if login_form.non_field_errors %}
                <div style="color:red";>
                    <p>{{login_form.non_field_errors}}</p>
                </div>

            {% endif %}
        </p>
    {% endfor %}
    <button type="submit">Log in</button>
</form>

{% endblock content %}

I'm just getting started with Django. I will be glad if you point out my mistake