handle Yahoo complaint for transactional email

email_handler.py

@@ -1479,6 +1479,12 @@ def handle_yahoo_complaint(msg: Message) -> bool:
         LOG.e("cannot find the alias")
         return False
 
+    user = User.get_by(email=to_header)
+    if user:
+        LOG.d("Handle transactional yahoo complaint for %s", user)
+        handle_yahoo_complain_for_transactional_email(user)
+        return True
+
     _, alias_address = parse_full_address(get_header_unicode(to_header))
     alias = Alias.get_by(email=alias_address)
 
@@ -1508,6 +1514,22 @@ def handle_yahoo_complaint(msg: Message) -> bool:
     return True
 
 
+def handle_yahoo_complain_for_transactional_email(user):
+    """Handle the case when a transactional email is set as Spam by user or by Yahoo"""
+    send_email_with_rate_control(
+        user,
+        ALERT_YAHOO_COMPLAINT,
+        user.email,
+        f"Yahoo abuse report",
+        render("transactional/yahoo-transactional-complaint.txt.jinja2", user=user),
+        render("transactional/yahoo-transactional-complaint.html", user=user),
+        max_nb_alert=1,
+        nb_day=7,
+    )
+
+    return True
+
+
 def handle_bounce_reply_phase(envelope, msg: Message, email_log: EmailLog):
     """
     Handle reply phase bounce

templates/emails/transactional/yahoo-transactional-complaint.html

@@ -0,0 +1,42 @@
+{% extends "base.html" %}
+
+{% block content %}
+  {% call text() %}
+    This is SimpleLogin team.
+  {% endcall %}
+
+  {% call text() %}
+    Yahoo has informed us about an email sent to <b>{{ user.email }}</b> that might have been considered as spam,
+    either by you or by Yahoo spam filter.
+  {% endcall %}
+
+  {% call text() %}
+    Please note that explicitly marking a SimpleLogin's forwarded email as Spam
+    affects SimpleLogin email delivery,
+    has a negative effect for all users and is a violation of our terms and condition.
+  {% endcall %}
+
+  {% call text() %}
+    If somehow Yahoo considers a forwarded email as Spam, it helps us if you can move the email
+    out of the Spam folder. You can also set up a filter to avoid this
+    from happening in the future using this guide at
+    https://simplelogin.io/docs/getting-started/troubleshooting/
+
+  {% endcall %}
+
+  {% call text() %}
+    Please don't put our emails into the Spam folder. This can end up in your account being disabled on SimpleLogin.
+  {% endcall %}
+
+  {% call text() %}
+    Looking to hear back from you.
+  {% endcall %}
+
+  {% call text() %}
+    Best, <br/>
+    SimpleLogin Team.
+  {% endcall %}
+
+{% endblock %}
+
+

templates/emails/transactional/yahoo-transactional-complaint.txt.jinja2

@@ -0,0 +1,22 @@
+Hi,
+
+This is SimpleLogin team.
+
+Yahoo has informed us about an email sent to {{ user.email }} that might have been considered as spam,
+either by you or by Yahoo.
+
+Please note that explicitly marking a SimpleLogin's forwarded email as Spam
+  affects SimpleLogin email delivery,
+  has a negative effect for all users and is a violation of our terms and condition.
+
+If somehow Yahoo considers a forwarded email as Spam, it helps us if you can move the email
+  out of the Spam folder. You can also set up a filter to avoid this
+  from happening in the future using this guide at
+  https://simplelogin.io/docs/getting-started/troubleshooting/
+
+Please don't put our emails into the Spam folder. This can end up in your account being disabled on SimpleLogin.
+
+Looking to hear back from you.
+
+Best,
+SimpleLogin Team.