diff --git a/app/jobs/fs/download_sent_message_related_messages_job.rb b/app/jobs/fs/download_sent_message_related_messages_job.rb
index 43f9fc69..7220f88a 100644
--- a/app/jobs/fs/download_sent_message_related_messages_job.rb
+++ b/app/jobs/fs/download_sent_message_related_messages_job.rb
@@ -9,6 +9,8 @@ def perform(outbox_message, from: nil, to: nil, fs_client: FsEnvironment.fs_clie
       0.step do |k|
         received_messages = fs_api.fetch_received_messages(sent_message_id: outbox_message.metadata['fs_message_id'], page: k + 1, count: batch_size, from: from, to: to)
 
+        raise "No related messages!" if outbox_message.thread.messages.excluding(outbox_message).none? && received_messages['messages'].none? && outbox_message.delivered_at < 1.hour.ago
+
         received_messages['messages'].each do |received_message|
           ::Fs::DownloadReceivedMessageJob.perform_later(received_message['message_id'], box: outbox_message.box)
         end
diff --git a/test/fixtures/boxes.yml b/test/fixtures/boxes.yml
index 87c00c55..0fa8a43c 100644
--- a/test/fixtures/boxes.yml
+++ b/test/fixtures/boxes.yml
@@ -77,6 +77,7 @@ fs_accountants:
   short_name: FSJJ
   api_connection: fs_api_connection1
   settings: {"dic": "1122334455", "subject_id": "df2f9373-30b7-4a44-9738-5b4e24e4866c", "message_drafts_import_enabled": true}
+  syncable: true
   type: 'Fs::Box'
 
 fs_accountants2:
diff --git a/test/fixtures/message_threads.yml b/test/fixtures/message_threads.yml
index 4cc60e30..65ac7df3 100644
--- a/test/fixtures/message_threads.yml
+++ b/test/fixtures/message_threads.yml
@@ -70,6 +70,13 @@ ssd_main_empty_draft:
   delivered_at: 2023-05-18 16:05:00
   last_message_delivered_at: 2023-05-18 16:05:00
 
+fs_accountants_outbox:
+  box: fs_accountants
+  title: Podanie
+  original_title: MyString
+  delivered_at: <%= 2.hours.ago %>
+  last_message_delivered_at: <%= 2.hours.ago %>
+
 solver_main_general_agenda:
   box: solver_main
   title: General agenda Solver
diff --git a/test/fixtures/messages.yml b/test/fixtures/messages.yml
index 7c252063..744b7946 100644
--- a/test/fixtures/messages.yml
+++ b/test/fixtures/messages.yml
@@ -289,6 +289,16 @@ ssd_main_empty_draft:
     correlation_id: <%= SecureRandom.uuid %>
   author: basic
 
+fs_accountants_outbox:
+  uuid: <%= SecureRandom.uuid %>
+  title: FS podanie
+  delivered_at: <%= 2.hours.ago %>
+  thread: fs_accountants_outbox
+  replyable: false
+  metadata:
+    fs_message_id: 1234/2024
+  author: accountants_basic
+
 solver_main_delivery_notification_one:
   uuid: bbff2617-3430-44c6-b827-519059ff1e90
   title: Authorized Delivery notification
diff --git a/test/jobs/fs/download_sent_message_related_messages_job_test.rb b/test/jobs/fs/download_sent_message_related_messages_job_test.rb
new file mode 100644
index 00000000..fa843ce8
--- /dev/null
+++ b/test/jobs/fs/download_sent_message_related_messages_job_test.rb
@@ -0,0 +1,20 @@
+require "test_helper"
+
+class Fs::DownloadSentMessageRelatedMessagesJobTest < ActiveJob::TestCase
+  test "raises error if no related messages for outbox_message" do
+    outbox_message = messages(:fs_accountants_outbox)
+
+    fs_api = Minitest::Mock.new
+    fs_api.expect :fetch_received_messages, {
+      "count" => 0,
+      "messages" => []
+    },
+    **{sent_message_id: outbox_message.metadata['fs_message_id'], page: 1, count: 25, from: nil, to: nil}
+
+    FsEnvironment.fs_client.stub :api, fs_api do
+      assert_raise(StandardError, match: /No related messages!/) do
+        Fs::DownloadSentMessageRelatedMessagesJob.new.perform(outbox_message)
+      end
+    end
+  end
+end