diff --git a/config/application.rb b/config/application.rb
index 5bbc596c16..39ea00770a 100644
--- a/config/application.rb
+++ b/config/application.rb
@@ -17,7 +17,7 @@
 module DomainNameRegistry
   class Application < Rails::Application
     config.load_defaults 6.0
-    config.autoloader = :zeitwerk # Do not use zeitwerk for now
+    config.autoloader = :zeitwerk
 
     # Settings in config/environments/* take precedence over those specified here.
     # Application configuration should go into files in config/initializers
diff --git a/config/sidekiq.yml b/config/sidekiq.yml
new file mode 100644
index 0000000000..0515ae2186
--- /dev/null
+++ b/config/sidekiq.yml
@@ -0,0 +1 @@
+:concurrency: 1
diff --git a/test/system/registrant_area/domains/domain_delete_confirms_test.rb b/test/system/registrant_area/domains/domain_delete_confirms_test.rb
deleted file mode 100644
index 259120b18f..0000000000
--- a/test/system/registrant_area/domains/domain_delete_confirms_test.rb
+++ /dev/null
@@ -1,42 +0,0 @@
-require 'application_system_test_case'
-
-class DomainDeleteConfirmsTest < ApplicationSystemTestCase
-  include ActionMailer::TestHelper
-  setup do
-    @user = users(:registrant)
-    sign_in @user
-
-    @domain = domains(:shop)
-    @domain.registrant_verification_asked!('<?xml version=\"1.0\" encoding=\"UTF-8\" standalone=\"no\"?>\n<epp></epp>', @user.id)
-    @domain.pending_delete!
-  end
-
-  def test_enqueues_approve_job_after_verification
-    visit registrant_domain_delete_confirm_url(@domain.id, token: @domain.registrant_verification_token)
-
-    click_on 'Confirm domain delete'
-
-    assert_text 'Domain registrant change has successfully received.'
-
-    assert_enqueued_jobs 1, only: DomainDeleteConfirmJob
-  end
-
-  def test_enqueues_reject_job_after_verification
-    visit registrant_domain_delete_confirm_url(@domain.id, token: @domain.registrant_verification_token)
-
-    click_on 'Reject domain delete'
-
-    assert_text 'Domain registrant change has been rejected successfully.'
-
-    assert_enqueued_jobs 1, only: DomainDeleteConfirmJob
-  end
-
-  def test_saves_whodunnit_info_after_verifivation
-    visit registrant_domain_delete_confirm_url(@domain.id, token: @domain.registrant_verification_token)
-    token =  @domain.registrant_verification_token
-    click_on 'Confirm domain delete'
-    assert_text 'Domain registrant change has successfully received.'
-
-    refute RegistrantVerification.find_by(verification_token:token).updator_str.empty?
-  end
-end