diff --git a/app/workers/introduce_account_pro_worker.rb b/app/workers/introduce_account_pro_worker.rb
index 520faa0b..3dc55f9c 100644
--- a/app/workers/introduce_account_pro_worker.rb
+++ b/app/workers/introduce_account_pro_worker.rb
@@ -15,6 +15,7 @@ class IntroduceAccountProWorker
   private
 
   def deliver_email(date_range)
+    return if @acct.nil? or @acct.user.nil?
     UserMailer.introduce_pro(@acct.user, date_range).deliver_now!
     @acct.user.touch(:last_emailed_at)
   end
diff --git a/app/workers/local_notification_worker.rb b/app/workers/local_notification_worker.rb
index 48635e49..9a4cbe21 100644
--- a/app/workers/local_notification_worker.rb
+++ b/app/workers/local_notification_worker.rb
@@ -4,13 +4,10 @@ class LocalNotificationWorker
   include Sidekiq::Worker
 
   def perform(receiver_account_id, activity_id = nil, activity_class_name = nil)
-    if activity_id.nil? && activity_class_name.nil?
-      activity = Mention.find(receiver_account_id)
-      receiver = activity.account
-    else
-      receiver = Account.find(receiver_account_id)
-      activity = activity_class_name.constantize.find(activity_id)
-    end
+    return true if activity_id.nil? or activity_class_name.nil?
+
+    receiver = Account.find(receiver_account_id)
+    activity = activity_class_name.constantize.find(activity_id)
 
     NotifyService.new.call(receiver, activity)
   rescue ActiveRecord::RecordNotFound