diff --git a/app/email_utils.py b/app/email_utils.py
index 54b9d767..582d1aa1 100644
--- a/app/email_utils.py
+++ b/app/email_utils.py
@@ -261,7 +261,7 @@ def send_email_with_rate_control(
         .count()
     )
 
-    if nb_alert > max_alert_24h:
+    if nb_alert >= max_alert_24h:
         LOG.error(
             "%s emails were sent to %s in the last 24h, alert type %s",
             nb_alert,
diff --git a/email_handler.py b/email_handler.py
index 658c6a65..6c76b4db 100644
--- a/email_handler.py
+++ b/email_handler.py
@@ -32,6 +32,8 @@ It should contain the following info:
 """
 import email
 import re
+
+import arrow
 import spf
 import time
 import uuid
@@ -480,7 +482,7 @@ def handle_reply(envelope, smtp: SMTP, msg: Message, rcpt_to: str) -> (bool, str
     mailbox: Mailbox = Mailbox.get_by(email=mailbox_email)
     if ENFORCE_SPF and mailbox.force_spf:
         ip = msg[_IP_HEADER]
-        if not spf_pass(ip, envelope, mailbox, user, alias, address):
+        if not spf_pass(ip, envelope, mailbox, user, alias, contact.website_email, msg):
             return False, "451 SL E11"
 
     delete_header(msg, _IP_HEADER)
@@ -554,7 +556,13 @@ def handle_reply(envelope, smtp: SMTP, msg: Message, rcpt_to: str) -> (bool, str
 
 
 def spf_pass(
-    ip: str, envelope, mailbox: Mailbox, user: User, alias: Alias, contact_email: str
+    ip: str,
+    envelope,
+    mailbox: Mailbox,
+    user: User,
+    alias: Alias,
+    contact_email: str,
+    msg: Message,
 ) -> bool:
     if ip:
         LOG.d("Enforce SPF")
@@ -583,6 +591,9 @@ def spf_pass(
                         alias=alias.email,
                         ip=ip,
                         mailbox_url=URL + f"/dashboard/mailbox/{mailbox.id}#spf",
+                        to_email=contact_email,
+                        subject=msg["Subject"],
+                        time=arrow.now(),
                     ),
                     render(
                         "transactional/spf-fail.html",
@@ -590,7 +601,13 @@ def spf_pass(
                         alias=alias.email,
                         ip=ip,
                         mailbox_url=URL + f"/dashboard/mailbox/{mailbox.id}#spf",
+                        to_email=contact_email,
+                        subject=msg["Subject"],
+                        time=arrow.now(),
                     ),
+                    # as the returned error status is 4**,
+                    # the sender will try to resend the email. Send the error message only once
+                    max_alert_24h=1,
                 )
                 return False
 
diff --git a/templates/emails/transactional/spf-fail.html b/templates/emails/transactional/spf-fail.html
index d8de6264..13558c58 100644
--- a/templates/emails/transactional/spf-fail.html
+++ b/templates/emails/transactional/spf-fail.html
@@ -4,10 +4,18 @@
   {{ render_text("Hi " + name) }}
 
   {% call text() %}
-    We have recorded an attempt to send an email from your alias <b>{{ alias }}</b> from an unknown IP address
+    We have recorded an attempt to send the following email from your alias <b>{{ alias }}</b> from an unknown IP
+    address
     <b>{{ ip }}</b>.
   {% endcall %}
 
+  {% call text() %}
+    - From: <b>{{ alias }}</b> <br>
+    - To: <b>{{ to_email }}</b> <br>
+    - Subject: <b>{{ subject }}</b> <br>
+    - Time: <b>{{ time.humanize() }}</b>
+  {% endcall %}
+
   {% call text() %}
     To prevent email-spoofing, SimpleLogin enforces the SPF (Sender Policy Framework).
     Emails sent from an IP address that is <b>unknown</b> by your email service are refused by default.
diff --git a/templates/emails/transactional/spf-fail.txt b/templates/emails/transactional/spf-fail.txt
index e7ba08e7..5cee2e6d 100644
--- a/templates/emails/transactional/spf-fail.txt
+++ b/templates/emails/transactional/spf-fail.txt
@@ -1,6 +1,11 @@
 Hi {{name}}
 
-We have recorded an attempt to send an email from your alias {{ alias }} from an unknown IP address {{ ip }}.
+We have recorded an attempt to send the following email from your alias {{ alias }} from an unknown IP address {{ ip }}.
+
+- From: {{alias}}
+- To: {{to_email}}
+- Subject: {{subject}}
+- Time: {{ time.humanize() }}
 
 To prevent email-spoofing, SimpleLogin enforces the SPF (Sender Policy Framework).
 Emails sent from an IP address that is unknown by your email service are refused by default.