Hello!

I successfully integrated Anymail with Django and can send test emails via the command line (using python manage.py sendtestmail [user@example.com](mailto:user@example.com)). The test email arrives in my Outlook inbox, and everything appears to work in both my development and production environments when I manually trigger the email. However, when a user registers via the live website, the email isn’t received even though I see the email content in the Heroku logs. There are no errors reported, and the user account is created normally (with a prompt to sign in again).

Below is the class-based view handling user registration and confirmation:

PYTHONCopied
class SignUpView(CreateView):
    model = Member
    template_name = "auth_app/signup.html"
    form_class = CustomUserCreationForm
    success_url = reverse_lazy("auth_app:signin")
    
    def dispatch(self, request, *args, **kwargs):
        """ Redirect authenticated users """
        if request.user.is_authenticated:
            return redirect("main_app:roomsPage")
        return super().dispatch(request, *args, **kwargs)
    
    def account_created_confirmation(self, username, user_email):
        subject = f"Welcome, {username}"
        from_email = os.environ.get("DEFAULT_FROM_EMAIL", "user@example.com")
        to_new_user = user_email
 
        text_content = render_to_string(template_name='auth_app/receipt_email.txt', context={"name": username})
        html_content = render_to_string(template_name='auth_app/receipt_email.html', context={"name": username})
 
        try:
            email = EmailMultiAlternatives(subject=subject, 
                                           body=text_content,
                                           from_email=from_email, 
                                           to=[user_email])
            
            email.attach_alternative(html_content, "text/html")
            email.send(fail_silently=False)
 
        except Exception as e:
            confirmation_email_sending_failed.error(f"Account register confirmation failed for user {username} with email: {user_email}. Error: {e}")
            raise Exception(f"Email sending failed to {to_new_user}. Error: {e}")
    
    def form_invalid(self, form):
        # Override form_invalid to ensure self.object is not accessed
        context = self.get_context_data(form=form)
        context.pop('object', None)  # Remove 'object' from context if it exists
        return self.render_to_response(context)
    
    def form_valid(self, form):
        policy_approved = form.cleaned_data["approve_policy"]
        user_profile_type = form.cleaned_data["profile_type"]
        username = form.cleaned_data["username"]
        user_email = form.cleaned_data["email"]
 
        if policy_approved:
            response = super().form_valid(form)
            self.account_created_confirmation(username, user_email)
            messages.success(self.request, _("Your account have been created. Please sign in to continue.")) 
            return response
        else:
            form.add_error("approve_policy", _"Please accept the user policy")
            return self.form_invalid(form)

Below are the relevant email settings:

PYTHONCopied
# Email back-end
EMAIL_BACKEND = 'anymail.backends.mailgun.EmailBackend'

ANYMAIL = {
    'MAILGUN_API_KEY': os.environ.get("MAILGUN_API_KEY"),
    'MAILGUN_SENDER_DOMAIN': os.environ.get("MAILGUN_SENDER_DOMAIN"),
    'MAILGUN_API_URL': os.environ.get("MAILGUN_API_URL"),
}

EMAIL_USE_TLS = True
DEFAULT_FROM_EMAIL = os.environ.get("DEFAULT_FROM_EMAIL")
SERVER_EMAIL = os.environ.get("SERVER_EMAIL")

What might be causing the email to not be sent on user registration in production? Any suggestions are appreciated!