Django: can't login after editing user details - django

Question

I'm trying to find a solution for 2 days now... can't figure out why login does not work for me once I have changed any user details.
Normal flow works fine for me: user registers, logs in and out without a problem. But I thought it would be good to have profile change option where a user can change username, password or email. I did implement this, but after a user changes anything (even email), the login form does not admit him.
Here is my views.py:
from django.contrib.auth.forms import UserCreationForm, UserChangeForm, PasswordChangeForm
from .forms import ContactForm, CreateUserForm, EditUserForm
class ProfileView(UpdateView):
template_name = 'boat_app/edit_profile.html'
form_class = UserChangeForm
success_url = reverse_lazy('anchored')
def get_object(self):
return self.request.user
class LoginView(TemplateView):
template_name = 'boat_app/login.html'
success_url = reverse_lazy('category_home')
def post(self, request):
print(request)
user = authenticate(request, username=request.POST.get('username'), password=request.POST.get('password'))
if user is not None:
print('user not none')
login(request, user)
return HttpResponseRedirect(reverse('anchored'))
else:
print('user none')
messages.info(request, 'Username OR password is incorrect')
return HttpResponseRedirect(reverse('login'))
And forms.py
from django.contrib.auth.forms import UserCreationForm, UserChangeForm
class EditUserForm(forms.ModelForm):
class Meta:
model = User
fields = ('username', 'email')
After changing a user I see this change in admin interface, so it does work. But I can't see a reason why the system does not see this relation. Any way to debug what exactly is going on there?
UPDATE
I've tried changing the user via admin backend - all works fine. I've also tried using {{ form.as_p }} instead of my custom template for ProfileView - and this also worked! So apparently there is something fishy going on with my html template which ruins the update view and does nont allow to collect data for future login.
Here is my 'boat_app/edit_profile.html'
{% block body_block %}
<div class="row align-items-center vh-100">
<div class="col-lg-4 d-none d-md-block">
</div>
<div class="col-lg-4 d-flex align-items-center">
<div class="container p-3 text-center bg-light">
<div class="my-3">
<h1>Change your details</h1>
<p>Did something change?</p>
</div>
<form method="post">
{% csrf_token %}
<div class="form-group row px-3">
<label for="{{ form.username.id_for_label }}">{{form.username.label}}</label>
{% render_field form.username class="form-control" %}
</div>
<div class="form-group row px-3">
{{ form.email.errors }}
<label for="{{ form.email.id_for_label }}">{{form.email.label}}</label>
{% render_field form.email class="form-control" %}
</div>
<div class="form-group row px-3">
{{ form.password.errors }}
<label for="{{ form.date_joined.id_for_label }}">{{form.date_joined.label}}</label>
{% render_field form.date_joined class="form-control" %}
</div>
<div class="form-group row text-left px-3">
<p>If you need to change password, click here.</p>
</div>
<button class="btn btn-primary" type="submit">Submit</button>
</form>
</div>
</div>
<div class="col-lg-4 d-none d-md-block">
</div>
</div>
{% endblock %}