diff --git a/app/models/forum_subscription.rb b/app/models/forum_subscription.rb
index d71c21753..8f1457282 100644
--- a/app/models/forum_subscription.rb
+++ b/app/models/forum_subscription.rb
@@ -13,7 +13,10 @@ class ForumSubscription < ActiveRecord::Base
       if forum_topic.updated_at > subscription.last_read_at
         CurrentUser.scoped(subscription.user, "127.0.0.1") do
           forum_posts = forum_topic.posts.where("created_at >= ?", subscription.last_read_at).order("id desc")
-          UserMailer.forum_notice(subscription.user, forum_topic, forum_posts).deliver
+          begin
+            UserMailer.forum_notice(subscription.user, forum_topic, forum_posts).deliver
+          rescue Net::SMTPSyntaxError
+          end
           subscription.update_attribute(:last_read_at, forum_topic.updated_at)
         end
       end