diff --git a/app/models/mail_handler.rb b/app/models/mail_handler.rb
index 44aed826f..2aaa8bbf0 100755
--- a/app/models/mail_handler.rb
+++ b/app/models/mail_handler.rb
@@ -274,7 +274,7 @@ class MailHandler < ActionMailer::Base
         add_attachments(reply)
         reply
       else
-        logger&.info "MailHandler: ignoring reply from [#{sender_email}] to a locked topic"
+        logger&.info "MailHandler: ignoring reply from [#{email.from.first}] to a locked topic"
       end
     end
   end
diff --git a/test/unit/mail_handler_test.rb b/test/unit/mail_handler_test.rb
index 447b2c5c2..469722a37 100644
--- a/test/unit/mail_handler_test.rb
+++ b/test/unit/mail_handler_test.rb
@@ -1002,6 +1002,17 @@ class MailHandlerTest < ActiveSupport::TestCase
     assert_equal Message.find(1), m.parent
   end
 
+  def test_reply_to_a_locked_topic
+    # Lock the topic
+    topic = Message.find(2).parent
+    topic.update_attribute :locked, true
+
+    assert_no_difference('topic.replies_count') do
+      m = submit_email('message_reply_by_subject.eml')
+      assert_not_kind_of Message, m
+    end
+  end
+
   def test_should_convert_tags_of_html_only_emails
     with_settings :text_formatting => 'textile' do
       issue = submit_email('ticket_html_only.eml', :issue => {:project => 'ecookbook'})