diff --git a/modules/smtp/modules.php b/modules/smtp/modules.php
index d4e268922d..d2c5704b63 100644
--- a/modules/smtp/modules.php
+++ b/modules/smtp/modules.php
@@ -1524,7 +1524,7 @@ function smtp_server_dropdown($data, $output_mod, $recip, $selected_id=false) {
             $smtp_profiles = profiles_by_smtp_id($profiles, $vals['id']);
             if (count($smtp_profiles) > 0) {
                 foreach ($smtp_profiles as $index => $profile) {
-                    $res .= '<option ';
+                    $res .= '<option data-email="'.$profile['address'].'"';
                     if ((string) $selected === sprintf('%s.%s', $vals['id'], ($index + 1)) || (! mb_strstr(strval($selected), '.') && strval($selected) === strval($vals['id']))) {
                         $res .= 'selected="selected" ';
                     }
@@ -1534,7 +1534,7 @@ function smtp_server_dropdown($data, $output_mod, $recip, $selected_id=false) {
                 }
             }
             else {
-                $res .= '<option ';
+                $res .= '<option data-email="'.$vals['user'].'"';
                 if ($selected === $id) {
                     $res .= 'selected="selected" ';
                 }
diff --git a/modules/smtp/site.js b/modules/smtp/site.js
index e08c0df92b..31981144c7 100644
--- a/modules/smtp/site.js
+++ b/modules/smtp/site.js
@@ -611,5 +611,37 @@ $(function () {
             $(".bubble_dropdown-content").remove();
             $(this).parent().remove();
         });
+
+        var selectedOption = $('#compose_smtp_id option[selected]');
+        var selectedEmail = selectedOption.data('email');
+        var selectedVal = selectedOption.val();
+
+        var recipientsInput = $('#compose_cc');
+        var excludedEmail = null;
+
+        const excludeEmail = function () {
+            var newRecipients = recipientsInput.val().split(',').filter(function(email) {
+                if (email.includes(selectedEmail)) {
+                    excludedEmail = email;
+                    return false;
+                }
+                return true;
+            }).join(', ');
+            recipientsInput.val(newRecipients);
+        };
+
+        if (recipientsInput.val().includes(selectedEmail)) {
+            excludeEmail();
+            $(document).on('change', '#compose_smtp_id', function() {
+                if ($(this).val() !== selectedVal) {
+                    if (!recipientsInput.val().includes(selectedEmail)) {
+                        recipientsInput.val(recipientsInput.val() + ', ' + excludedEmail);
+                    }
+                } else {
+                    excludeEmail();
+                }
+            });
+        }
+
     }
 });